Introduction^[1]

The Inca Empire^[2] flourished in modern-day Peru from the 13^th to the 16^th century and was renowned for its impressive engineering feats. The Incans were masters of engineering, and their remarkable structures and techniques continue to fascinate and inspire people today. The Empire was renowned for its highly skilled stonemasonry and hydraulic engineering, which allowed them to build impressive structures and manage their extensive agricultural systems in the challenging Andean environment. This paper looks at some of the most notable examples.

Caption: “Machu Picchu Close-Up” by szeke is licensed under CC BY-NC-SA 2.0.

Locations

Machu Picchu^[3]
Perhaps the most famous Incan engineering marvel of all, Machu Picchu is a citadel built atop a mountain ridge at an elevation of 2,430 metres (7,970 ft), located above the Sacred Valley, 80 km (50 mi) northwest of Cusco, with the important Urubamba River flowing past it.

Once labelled ‘the Lost City’, the complex was constructed using a technique called ashlar^[4] in which stones are cut to fit together perfectly without using mortar. Machu Picchu also features a sophisticated system of terraces and irrigation channels that allowed the Inca to grow crops on steep mountain slopes. Machu Picchu was probably built as a royal estate for Emperor Pachacuti, (also called Pachacutec) (1438–1472), sometime around 1450 AD^[5].

Saksaywaman^[6]
This fortress, located near the Inca capital of Cusco, features massive stone walls constructed using the ashlar technique. Some of the stones used in the walls weigh as much as 200 tons and are fitted together so precisely that not even a blade of grass can fit between them. The fortress also features a complex system of underground tunnels and water channels. Sacsayhuaman was the most important military base of the Inca Empire, and has been compared in greatness with the Roman Colosseum. The whole structure is a hugely impressive work of engineering^[7].

Ollantaytambo ^[8]
This archaeological site features a large complex of stone buildings, including a temple and a series of terraces that were used for agricultural purposes. The site also includes a system of underground water channels that allowed the Inca to irrigate their crops.

Qhapaq Ñan ^[9]
This vast network of roads, stretching over 40,000 kilometres (25,000 miles), connected the various regions of the Inca Empire. The roads were constructed using a combination of cut-stone paving and dirt and gravel fill and were designed to withstand earthquakes and other natural disasters. Along the roads, the Inca built rest houses and storage facilities to support their armies and administrative officials. The road network can be directly compared with the road network built during the Roman Empire, although the Inca road system was built a thousand years later^[10].

Pisac ^[11]
This Inca ruin features a complex of agricultural terraces that were built on a steep mountainside. The terraces were constructed using a technique called andenes, in which retaining walls are built to create level areas for planting crops. The site also includes a series of finely crafted stone structures, including a temple and a large ceremonial plaza.

Tambomachay ^[12]
This site, located near Cusco, features a series of aqueducts, canals, and fountains used for bathing and religious ceremonies. The water was sourced from nearby springs and routed through a series of channels and reservoirs to create a complex system of flowing water.

Caption: Andenes at Moray, Peru
Attribution: Philipp Weigell, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0&gt;, via Wikimedia Commons
Page URL: https://commons.wikimedia.org/wiki/File:Moray_-_Qechuyoq.JPG

This file is licensed under the Creative Commons Attribution 3.0 Unported license.

Moray ^[13]
This site features a series of circular terraces for agricultural experimentation. The terraces were built into a natural depression in the landscape, and each one had a slightly different microclimate that allowed the Inca to test the growing conditions for different crops.

Tipón ^[14]
This site features a complex system of agricultural terraces and irrigation channels to grow crops in the dry Andean climate. The terraces were designed to capture and retain water from nearby springs, and the channels distributed the water evenly across the agricultural fields.

Choquequirao ^[15]
This site, sometimes called the “sister city” of Machu Picchu, features a large complex of buildings and terraces used for religious and agricultural purposes. The site is located at a high elevation, and its construction required transporting large quantities of stone and other materials over difficult terrain.

Sayhuite
Sayhuite is an archaeological site 47 kilometres (29 mi) east of the city of Abancay, about 3 hours away from the city of Cusco, in the province of Abancay in the region Apurímac in Peru.^[16]  The site is regarded as a centre of religious worship for the Inca people, focusing on water.^[17] In the Monuments of the Inca by John Hemming, the author points to a colonial narrative that describes the interior of the Sayhuite temple. The temple featured larger columns draped in fabrics with gold bands the “thickness of one’s hand.” The temple was also under the care of the priestess Asarpay, who jumped to her death in the nearby 400-metre gorge to avoid capture by Spanish forces.^[18]

Caption: Sayhuite Archaeological site (rock sculpture)
Attribution: I, AgainErick, CC BY-SA 3.0 <http://creativecommons.org/licenses/by-sa/3.0/&gt;, via Wikimedia Commons
Page URL: https://commons.wikimedia.org/wiki/File:Sayhuite_Archaeological_site_-_rock_sculpture.jpg

This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.

Inca Buildings
Inca architecture is famous for its incredible stonework, with Machu Picchu being the best-known example. Other notable Inca ruins include the Fortress of Sacsayhuamán, Ollantaytambo, and the Coricancha Temple.

A rectangular-shaped building with wooden beams and thatched roofs was the most common type of construction in Inca architecture. This design was used in almost all buildings, from houses to temples, and formed the basis for Inca urban planning. Incan cities and towns were typically designed with several rectangular buildings surrounding a central plaza known as a kancha^[19]. Multiple kancha would then be arranged to form city blocks.

At the heart of Cusco, the former capital of the Inca empire, lies the Coricancha Temple, also known as the Temple of the Sun. This temple was the most important religious building of the Inca empire and was reserved for the Sapa Inca (the Inca emperor), his immediate family, priests, and the chosen women to worship. The temple was said to be decorated with gold and silver, and even the walls were lined with sheets of gold. Despite being a centre for pilgrimage, the general public was not allowed inside the temple.

In addition to their impressive stonework and architectural achievements, the Inca were also skilled engineers. They built an extensive network of roads and bridges, including the famous Inca Trail, which was used to transport goods and people across the empire. The Inca were also known for their advanced agricultural practices, such as terracing and irrigation, which allowed them to cultivate crops in the steep Andean terrain.

Construction Projects, Techniques and Systems

Caption: Trimmed mat rolls form the bridge deck.
Attribution: CREDIT: Photo courtesy of Rutahsa Adventures http://www.rutahsa.com – uploaded with permission by User:Leonard G. at en.wikipedia, CC BY-SA 1.0 <https://creativecommons.org/licenses/by-sa/1.0&gt;, via Wikimedia Commons
Page URL: https://commons.wikimedia.org/wiki/File:IRB-6-BringingDeckMat-KC603-8.jpg

This file is licensed under the Creative Commons Attribution-Share Alike 1.0 Generic license.

Suspension Bridges
The Inca constructed a series of impressive suspension bridges across rivers and canyons throughout their empire. These bridges were made using natural fibres such as grass or ichu and were designed to be strong enough to support the weight of both people and animals. Some of the bridges were over 150 feet long, and were suspended at heights of up to 200 feet above the ground.

Terracing
The Inca constructed thousands of terraces throughout their empire to cultivate crops in the mountainous terrain. The terraces were built into the steep slopes of the Andes and were designed to maximize the amount of arable land available. The Inca used a combination of retaining walls, filling material, and irrigation channels to create flat, level surfaces for planting crops.

Agriculture
The Inca developed sophisticated agricultural techniques that allowed them to cultivate a wide variety of crops in the challenging Andean environment. These techniques included crop rotation, soil conservation, and using fertilisers made from guano (bird droppings) and other organic materials.

Water Management Systems
The Inca developed a complex system of canals, aqueducts, and reservoirs to manage their water resources. They constructed large stone channels to divert water from mountain streams and directed it to agricultural terraces and urban centres. The Inca also built underground channels and reservoirs to store water for dry periods.

Masonry
The Inca were renowned for their masterful stonework, seen in many structures, including Machu Picchu, Sacsayhuaman, and Ollantaytambo. They used a technique called ashlar masonry, in which large stones were cut and fitted together with such precision that not even a blade of grass could fit between them. The Inca also used a technique called polygonal masonry, in which irregularly shaped stones were pieced together like a jigsaw puzzle.

A trapezoidal doorway, a common element in Inca architecture, at Machu Picchu
Attribution: Riccardo Specchia, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0&gt;, via Wikimedia Commons
Page URL: https://commons.wikimedia.org/wiki/File:Macchu_Picchu_Stones_2.jpg

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Astronomy
The Inca were skilled astronomers and developed a sophisticated understanding of the movements of the sun, moon, and stars. They built observatories, such as the one at Machu Picchu, to study the sky and developed calendars that helped them track the passage of time and plan their agricultural activities.

Communication System
The Inca developed a system of communication that relied on a network of runners who carried messages over long distances. These runners were highly trained and could cover up to 240 km (150 miles) in a single day. Along the roads, the Inca built rest houses and storage facilities to support the runners and provide them with supplies.

Military Architecture
The Inca constructed various military structures, including fortresses, watchtowers, and walls, to defend their empire against invaders. These structures were designed to be strategically located and difficult to penetrate, with features such as steep slopes, narrow entryways, and hidden traps.

Hydraulic Mining
The Inca developed a sophisticated system of hydraulic mining to extract gold and silver from the mountains. They used water to erode the soil, expose the minerals, and collect sediment in sluices and channels. The Inca also developed techniques for refining the metals, such as smelting and hammering.

Acoustics
The Inca were skilled at using sound to communicate over long distances and create dramatic effects in their buildings. They built spaces with carefully calculated dimensions and angles to create echoes and amplify sounds, such as in the temple of Coricancha in Cusco.

Inca Textiles
The Inca were skilled weavers and produced intricate textiles using a variety of techniques, such as backstrap weaving and embroidery. They used natural dyes to create vibrant colours and intricate patterns, and their textiles were highly valued for their beauty and durability.

Inca Metallurgy
The Inca were skilled metalworkers and produced a variety of objects, including tools, weapons, and jewellery, using gold, silver, copper, and bronze. They used casting, hammering, and soldering techniques to create objects of great beauty and functionality.

Medicine
The Inca developed a sophisticated system of medicine that relied on a combination of natural remedies, such as herbs and plants, and spiritual practices, such as prayer and ritual. They also developed surgical techniques, such as trepanation, and used natural materials, such as obsidian, to make surgical tools.

Construction Skills

Masonry
As already mentioned, the Inca were renowned for their use of ashlar masonry, a technique in which stones are cut and fitted together with such precision that not even a blade of grass can fit between them. The Inca used this technique to construct many of their most impressive structures, including Machu Picchu, Sacsayhuaman, and Ollantaytambo.

In addition to ashlar masonry, the Inca also used a technique called polygonal masonry, in which irregularly shaped stones were fit together like a jigsaw puzzle. This technique allowed the Inca to construct walls and other structures with curved or angled shapes.

Hydraulic Engineering
The Inca developed a sophisticated system of hydraulic engineering to manage their water resources. They constructed large stone channels to divert water from mountain streams and directed it to agricultural terraces and urban centres. The Inca also built underground channels and reservoirs to store water for dry periods.

Terracing
The Inca constructed thousands of terraces throughout their empire to cultivate crops in the mountainous terrain. The terraces were built into the steep slopes of the Andes and were designed to maximize the amount of arable land available. The Inca used a combination of retaining walls, fill material, and irrigation channels to create flat, level surfaces for planting crops.

Road Construction
The Inca constructed a vast network of roads, stretching over 40,000 kilometres (25,000 miles), to connect the various regions of their empire. The roads were constructed using a combination of cut-stone paving and dirt and gravel fill and were designed to withstand earthquakes and other natural disasters. The roads made it possible for government officials to travel around the empire. Roads also encouraged trade. Most importantly, the roads allowed the army to travel quickly. This way, they could put down a rebellion or enforce the emperor’s rule. The Royal Road was twenty-four feet wide in most places. Although it crossed mountains, valleys, deserts, and swamps, long stretches were straight like arrows.^[20]

Masonry Tools
The Inca used a variety of tools to cut and shape their stones, including chisels, hammers, and wedges made of bronze, copper, and stone. They also used tools made of harder materials, such as obsidian, to cut the softer stones.

Masonry Techniques
The Inca used various techniques to cut and shape their stones, including pecking, grinding, and polishing. They also used a method called “toothed hammering,” in which the stone’s surface was hammered with a tool with teeth on it, creating a rough surface that allowed the stones to fit together more tightly.

Masonry Precision
The precision of Inca masonry was remarkable, with stones fitting together so perfectly that not even a knife blade could fit between them. The Inca achieved this level of precision through careful planning and measurement, as well as the use of templates and guides to ensure that each stone was cut to the correct size and shape.

Masonry Variations
The Inca used various masonry techniques and styles to create different effects in their buildings. For example, they used rough stones to create a more natural look in some structures and polished stones to create a more refined look in others. They also used different types of stones, such as granite and limestone, to create contrast and variation.

Earthquake Resistance
The Inca were skilled at designing structures that could withstand earthquakes, which were common in the Andean region. They used various techniques to create earthquake-resistant structures, including trapezoidal doorways, which distribute the weight of the building more evenly, and building structures on foundations of layered stones, which allow for greater flexibility during earthquakes.

Thermal Insulation
The Inca were skilled at creating well-insulated buildings to maintain a comfortable temperature in the Andean climate. They used various materials, such as straw, mud, and adobe, to build walls and roofs that provided thermal insulation.

Stonework Symbolism
The Inca used stonework to convey symbolic and spiritual meanings in their buildings. For example, they used the shape of the puma’s head in the design of some buildings, symbolising strength and power. They also used the shape of the condor’s wings in the design of other buildings to represent freedom and flight.

Water Management Design
The Inca designed their water management systems with great care, using principles of gravity and hydraulics to ensure water flowed smoothly and efficiently. They used aqueducts, canals, and reservoirs to move water from high elevations to low elevations and used retaining walls and other structures to control the flow of water and prevent erosion.

Building Placement
The Inca carefully selected the locations for their buildings based on factors such as the availability of resources, the terrain, and the site’s spiritual significance. They often built their structures on high elevations, which provided strategic advantages and allowed them to connect with the spiritual world.

Building Planning
The Inca engaged in careful planning and design of their buildings, using a combination of mathematical principles and trial-and-error experimentation to create functional, beautiful, and durable structures. They often used templates and guidelines to ensure each building component was cut and fitted precisely.

Building Sustainability
The Inca built their structures to last, using durable materials and sustainable construction techniques. They often used locally sourced materials, such as stone and mud, and employed methods such as terracing and irrigation to create sustainable agricultural systems that supported their communities.

Building Adaptability
The Inca were skilled at adapting their building techniques and designs to suit different environments and contexts. They used different materials and styles depending on the region and created structures suited to their communities’ specific needs.

Building Integration with Landscape
The Inca were skilled at integrating their buildings with the natural landscape, creating structures that blended seamlessly with the environment. They often used the land’s natural contours to shape their buildings and incorporated local materials and vegetation into their designs.

Building Functionality
The Inca built their structures with functionality in mind, creating buildings that were well-suited to their intended purposes. They often used different types of structures for different functions, such as residential structures, storage structures, and ceremonial structures.

Building Decoration
The Inca decorated their buildings with various symbols and motifs, using intricate carvings, paintings, and textiles to create beautiful and meaningful designs. They used these decorations to convey spiritual and cultural messages and create a sense of beauty and harmony in their surroundings.

Building Flexibility
The Inca built their structures with a certain degree of flexibility, allowing them to adapt to changing conditions and needs. For example, they often used removable roof tiles that could be replaced or repositioned as needed, and they built structures with multiple entrances and exits to allow for different uses.

Building Sound Engineering
The Inca were skilled at creating buildings with good acoustics, using careful design and construction techniques to create spaces with optimal sound quality. They often used curves and angles in their structures to create echoes and amplify sound, and they built structures with specific purposes in mind, such as music or ceremony.

Building Sustainability
The Inca were skilled at creating sustainable buildings and systems, using techniques such as terracing and irrigation to create sustainable agriculture, and using natural materials and energy-efficient designs to create sustainable structures. They also incorporated spiritual and cultural values into their designs, creating functional, meaningful, and inspiring buildings.

Skills and Uniqueness
The skills of the Inca Empire were developed over centuries of trial and error and were refined through experimentation, observation, and innovation. The Inca drew on the knowledge and expertise of previous civilisations in the Andean region, including the Wari and Tiwanaku cultures, as well as on their own cultural and spiritual traditions.

The Inca Empire’s construction skills were unique and remarkable for their time. The Inca’s ability to create precise, durable, and aesthetically pleasing structures using only simple tools and local materials was a significant achievement. Their systems for water management, agriculture, and communication were also highly advanced and represented a level of unparalleled sophistication in the Andean region.

One of the reasons why the Inca Empire’s construction skills were so impressive was the difficult terrain in which they built their structures. The Andean region is characterised by steep mountains, deep valleys, and extreme weather conditions, which presented significant challenges for builders and engineers. Despite these challenges, the Inca created a vast network of roads, aqueducts, and terraces that allowed them to thrive in this harsh environment.

The Inca’s construction skills were also notable for their spiritual and cultural significance. They viewed their buildings and systems as integral parts of their spiritual and cultural identity and incorporated symbolic and ritual elements into their designs. This attention to symbolism and cultural values gave their structures a sense of meaning and purpose beyond mere functionality.

Time Period
The Inca Empire existed from the 13^th century until the Spanish conquest in the 16^th century. Their civilisation peaked during the 15^th century when they controlled a vast territory that extended from modern-day Ecuador to Chile.

The Inca’s impressive engineering and construction skills were developed over centuries, as the empire grew and expanded its territory. Their mastery of these skills allowed them to create a highly organised and efficient society that could thrive in the challenging Andean environment.

What drew the Inca to that part of Peru?
The Inca were originally a small tribe from the Cusco region of southern Peru, which is located in the Andean mountains. According to Inca mythology, their legendary founder, Manco Capac, emerged from the waters of Lake Titicaca and travelled north to establish the Inca Empire. In reality, it is believed that the Inca gradually expanded their territory through a combination of conquest and diplomacy.

The region around Cusco was rich in natural resources, including gold, silver, and fertile agricultural land, which may have been a factor in the Inca’s decision to settle there. The Andean environment also presented challenges, such as steep slopes and extreme weather conditions, which may have encouraged the Inca to develop their engineering and construction skills to overcome these obstacles.

The Inca’s proximity to other civilisations in the Andean region, such as the Wari and Tiwanaku cultures, may have also influenced their development. The Inca drew on the knowledge and expertise of these earlier civilisations and their own cultural and spiritual traditions to create a unique and sophisticated society that could thrive in the challenging Andean environment.

Caption: [Cropped] “Map of the Sacred Valley of the Incas, Peru, 2002” by travfotos is licensed under CC BY-NC 2.0.

Sources and Further Reading

• http://incamayanaztec.com/inca-engineers.html
• http://www.discover-peru.org/inca-architecture
• https://americanindian.si.edu/inkaroad/engineering/index.html
• https://en.wikipedia.org/wiki/Choquequirao
• https://en.wikipedia.org/wiki/Inca_Empire
• https://en.wikipedia.org/wiki/Inca_road_system
• https://en.wikipedia.org/wiki/Inca_technology
• https://en.wikipedia.org/wiki/Manco_Capac
• https://en.wikipedia.org/wiki/Machu_Picchu
• https://en.wikipedia.org/wiki/Moray_(Inca_ruin)
• https://en.wikipedia.org/wiki/Ollantaytambo
• https://en.wikipedia.org/wiki/Pisac
• https://en.wikipedia.org/wiki/Sacsayhuaman
• https://en.wikipedia.org/wiki/Tambomachay
• https://en.wikipedia.org/wiki/Tipon
• https://en.wikipedia.org/wiki/Tiwanaku_Empire
• https://en.wikipedia.org/wiki/Wari_Empire
• https://theculturetrip.com/south-america/bolivia/articles/8-things-you-didnt-know-the-incas-invented/
• https://thpt-macdinhchi-tphcm.edu.vn/how-did-the-inca-use-their-engineering-skills-to-manage-and-grow-their-empire/
• https://www.ancient-origins.net/ancient-places-americas/inca-engineering-0018359
• https://www.ancient-origins.net/history-famous-people/pachacuti-0015068
• https://www.ancient-origins.net/weird-facts/inca-rope-bridges-0018010
• https://www.annees-de-pelerinage.com/machu-picchu-architecture-explained
• https://www.bbc.com/travel/article/20211212-the-innovative-technology-that-powered-the-inca
• https://www.guadalupe-school.org/wp-content/uploads/2020/06/chapter6_Inca.engineering-1.pdf
• https://www.pbs.org/wgbh/nova/article/wright-inca-engineering/
• https://www.smithsonianmag.com/history/earliest-and-greatest-engineers-were-incans-180947976/
• https://www.tcsworldtravel.com/article/inca-ancient-masters-of-stonework-and-civil-engineering
• https://www.worldhistory.org/Inca_Architecture/

Books

• Monuments of the Inca, by John Hemming and Edward Ranney, 22 Feb 2010, published by Thames & Hudson, available at: https://www.amazon.co.uk/Monuments-Incas-John-Hemming/dp/0500051631
• Inca architecture, by Gasparini, Graziano,1984, published by Indiana University Press, available at: https://www.amazon.co.uk/Inca-Architecture-Gasparini-Publisher-Hardcover/dp/B00SLSQZ34/
• Inca settlement planning, by John Hyslop, 1990, published by University of Texas Press, available at: https://www.amazon.co.uk/Inca-Settlement-Planning-John-Hyslop/dp/0292738528
• Inca architecture and construction at Ollantaytambo, by Jean-Pierre Protzen, 1993, published by Oxford University Press, available at: https://www.amazon.co.uk/Architecture-Construction-Ollantaytambo-Jean-Pierre-1993-07-08/dp/B01A64UHUW/
• At home with the Sapa Inca: Architecture, Space, and Legacy at Chinchero, by Stella Nair, 2015, published by University of Texas Print, available at: https://www.amazon.co.uk/Home-Sapa-Inca-Architecture-Recovering/dp/1477302506/
• An introduction to the archaeology of Cuzco, by John Howland Rowe, 1944, published by Harvard University, available at: https://www.amazon.co.uk/Introduction-Archaeology-Expeditions-southern-University/dp/B0007GUWY6/
• Empire and Domestic Economy, by Terence N D’Altroy and Christine A. Hastorf, 2010, published by Springer, available at: https://www.amazon.co.uk/Domestic-Economy-Interdisciplinary-Contributions-Archaeology/dp/1441933433/
• The Development of the Inca State, by Brian Bauer, 1996, published by the University of Texas Press, available at: https://www.amazon.co.uk/Development-Inca-State-Brian-Bauer/dp/0292708483/
• Intrepid Dudettes of the Inca Empire, by Helen Pugh, 2020, published by author, available at:
• https://www.amazon.co.uk/Intrepid-Dudettes-Inca-Empire-Helen/dp/B098WHLWPG/
• The Inca Empire: An Enthralling Overview of the Incas, Their Civilization in Ancient Peru, and the Spanish Conquest (Mesoamerica), Paperback, by Billy Wellman (Author) and publisher, 15 April 2023, available at: https://www.amazon.co.uk/Inca-Empire-Enthralling-Civilization-Mesoamerica/dp/B0C1JGTVT9/
• The Inca: Lost Civilizations, Hardcover – Illustrated, by Kevin Lane (Author), 14 Feb. 2022, published by Reaktion Books, available at: https://www.amazon.co.uk/Inca-Lost-Civilizations-Kevin-Lane/dp/1789145465/
• Lost City of the Incas, Paperback – Illustrated, by Hiram Bingham (Author), Hugh Thomson (Introduction), 3 April 2003, published by Weidenfeld and Nicholson, available at: https://www.amazon.co.uk/Lost-City-Incas-Phoenix-Press/dp/1842125850/
• The Inca: An Introduction to Inca History, Myth, Gods and Goddesses, and the Rise and Fall of the Ancient Inca Civilization, Hardcover, by Marie Campbell (Author), 28 Nov. 2022, self published, available at: https://www.amazon.co.uk/Inca-Introduction-History-Goddesses-Civilization/dp/B0BMXS44NZ/
• Machu Picchu: Unveiling the Mystery of the Incas, Paperback, by Richard L Burger (Author), Lucy C Salazar (Author), 1 April 2008, published by Yale University Press, available at: https://www.amazon.co.uk/Machu-Picchu-Unveiling-Mystery-Incas/dp/0300136455/

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End Notes and Explanations

1. Source: Compiled from research using information at the sources stated throughout the text, together with information provided by machine-generated artificial intelligence at: bing.com [chat] and https://chat.openai.com ↑
2. Explanation: The Inca Empire (also known as the Incan Empire and the Inka Empire), called Tawantinsuyu by its subjects, (Quechua for the “Realm of the Four Parts”) was the largest empire in pre-Columbian America. The administrative, political and military centre of the empire was in the city of Cusco. The Inca civilisation arose from the Peruvian highlands sometime in the early 13^th century. The Spanish began the conquest of the Inca Empire in 1532 and by 1572, the last Inca state was fully conquered. Source: https://en.wikipedia.org/wiki/Inca_Empire ↑
3. Source: https://en.wikipedia.org/wiki/Machu_Picchu ↑
4. Explanation: The technique of fitting stones together without mortar is known as Ashlar. The Inca refrained from using mortar because the loose-fitting of ashlar was more resistant to earthquakes and the whole Urubamba Valley was prone to experiencing them. Source: https://www.annees-de-pelerinage.com/machu-picchu-architecture-explained ↑
5. Source: https://www.ancient-origins.net/ancient-places-americas/inca-engineering-0018359 ↑
6. Explanation: Sacsayhuamán, often spelled Saqsaywaman or Xacxaguaman, (possibly from Quechua language, waman falcon or variable hawk), is a citadel on the northern outskirts of the city of Cusco, Peru, the historic capital of the Inca Empire. The site is at an altitude of 3,701 m (12,142 ft). The complex was built by the Incas in the 15^th century, particularly under Sapa Inca Pachacuti and his successors. Dry stone walls constructed of huge stones were built on the site, with the workers carefully cutting the boulders to fit them together tightly without mortar (a method known as Ashlar). In 1983, Cusco and Sacsayhuamán together were designated as sites on the UNESCO World Heritage List, for international recognition and protection. The site is now constantly explored by tourists. Source: https://en.wikipedia.org/wiki/Sacsayhuaman ↑
7. Source: https://www.peruhop.com/sacsayhuaman-all-you-need-to-know/ ↑
8. Explanation: Ollantaytambo is a town and an Inca archaeological site in southern Peru some 72 km (45 mi) by road northwest of the city of Cusco. It is located at an altitude of 2,792 m (9,160 ft) above sea level in the district of Ollantaytambo, province of Urubamba, Cusco region. During the Inca Empire, Ollantaytambo was the royal estate of Emperor Pachacuti, who conquered the region and built the town and a ceremonial centre. At the time of the Spanish conquest of Peru, it served as a stronghold for Manco Inca Yupanqui, leader of the Inca resistance. Located in the Sacred Valley of the Incas, it is now an important tourist attraction on account of its Inca ruins and its location en route to one of the most common starting points for the four-day, three-night hike known as the Inca Trail. Source: https://en.wikipedia.org/wiki/Ollantaytambo ↑
9. Explanation: The Inca road system (also spelled Inka road system and known as Qhapaq Ñan (meaning “royal road” in Quechua) was the most extensive and advanced transportation system in pre-Columbian South America. It was about 40,000 kilometres (25,000 mi) long.  The construction of the roads required a large expenditure of time and effort. Source: https://en.wikipedia.org/wiki/Inca_road_system ↑
10. Source: Mattos, Ramiro (2015). El Qhapaq Ñan del Tawantinsuyu: reflexiones sobre su significado político y social en el presente andino – Revista de Antropología del Museo de Entre Ríos 12-20 (2015). Cited at: https://en.wikipedia.org/wiki/Inca_road_system ↑
11. Explanation: Pisac (possibly from Quechua for Nothoprocta, also spelled p’isaqa) is a Peruvian town in the Sacred Valley of the Incas. It is situated on the Vilcanota River. Pisac is most known for its Incan ruins and large market which attracts heavy tourist traffic from nearby Cusco. The remains of Lucre and Killke pottery that have been found in the area, suggest that the district has been occupied for some time. An early settlement which probably pre-dated the Inca existed on the hillside between the Quitamayo and Chongo tributaries of the Vilcanota river. This community raised their crops on terraces as well as on the flood plain. Later as the threats from other tribes declined the villagers moved closer to the main road to Cusco and Urcos. Source: https://en.wikipedia.org/wiki/Pisac ↑
12. Explanation: Tambomachay (possibly from Quechua tampu inn, guest house, mach’ay cave, or machay drunkenness, to get drunk or “spindle with thread”) is an archaeological site associated with the Inca Empire, located near Cusco, Peru. An alternate Spanish name is El Baño del Inca (“the bath of the Inca”). It consists of a series of aqueducts, canals and waterfalls that run through the terraced rocks. It is situated near springs such as the one called Timpuc Puquiu, a boiling spring on the northern bank of the Timpuc River and the spring near Huaylla Cocha community. These natural springs were channeled through three waterfalls that still flow today. The function of the site is uncertain: it may have served as a military outpost guarding the approaches to Cusco, as a spa resort for the Incan political elite or imperial baths. It could have also served a religious function since sacred water fountains were found almost all of major Incan temple such as Pisac, Ollantaytambo, and Machu Picchu. There are sources that refer to Tambomachay as one of the nine ceques built along the Road of Antisuyu, describing it as an Incan house where sacrifices were also made. Source: https://en.wikipedia.org/wiki/Tambomachay ↑
13. Explanation: Moray (Quechua: Muray)^[3] is an archaeological site in Peru approximately 50 kilometres (31 mi) northwest of Cuzco on a high plateau at about 3,500 metres (11,500 ft) and just west of the village of Maras. The site contains Inca ruins, mostly consisting of several terraced circular depressions, the largest of which is approximately 30 m (98 ft) deep. As with many other Inca sites, it also has an irrigation system. During the rainy season of 2009–2010, the Department of Cusco received high levels of precipitation that are atypical, which caused permanent damage to the ruins of Moray. The terraced levels of the complex, which are constructed from stone and compacted earth, were damaged extensively as the excessive rain waters undermined the ground beneath the structure. Source: https://en.wikipedia.org/wiki/Moray_(Inca_ruin) ↑
14. Explanation: Tipón is a sprawling early 15^th century Inca archaeological park that is situated between 3,250 metres (10,660 ft) and 3,960 metres (12,990 ft) above sea level, located 22 kilometres (14 mi) southeast of Cusco near the village of Tipón.  It consists of several ruins enclosed by a powerful defensive wall about 6 kilometres (3.7 mi) long. The most renown (and easily accessible) part of the park is the group of precise and right angled monumental terraces irrigated by a network of water canals fed by a monumental fountain channeling water from a natural spring. The site includes ancient residential areas and a remarkable amount of petroglyphs in its upper part. The irrigation system based on canals, fountains and stonework with water drop structures shows that the Incas had an advanced water related technology and were experienced hydraulic engineers. Since 1970’s the area has been excavated and restored. Most probably the Tipón complex was an imperial Inca estate or at least a sort of feudal estate for Inca elite built in the time of Pachacuti or his son, Topa Inca Yupanqui and it is supposed that also ceremonial activities took place in it. The site may have also been used as a laboratory for agricultural products because of the various micro-climates found within the complex, a reliable round-the-year water supply and the fertile soil. Tipón is considered one of the most important archaeological tours for tourists who visit the Cusco area. The Tipón complex is located near Oropesa in the Community of Choquepata, Quispicanchi Province, southeast of Cusco, along the Cusco-Puno road. Tipón is considered one of the most important archaeological tours for tourists who visit the Cusco area. Source: https://en.wikipedia.org/wiki/Tipon ↑
15. Explanation: Choquequirao (possibly from Quechua chuqi metal, k’iraw crib, cot) is an Incan site in southern Peru, similar in structure and architecture to Machu Picchu. The ruins are buildings and terraces at levels above and below Sunch’u Pata, the truncated hill top. The hilltop was anciently levelled and ringed with stones to create a 30 by 50 m platform. Choquequirao at an elevation of 3,050 metres (10,010 ft) is in the spurs of the Vilcabamba mountain range in the Santa Teresa district, La Convención Province of the Cusco Region. The complex is 1,800 hectares, of which 30–40% is excavated. The site overlooks the Apurimac River canyon that has an elevation of 1,450 metres (4,760 ft). The site is reached by a two-day hike from outside Cusco. Choquequirao has topped in the prestigious Lonely Planet’s Best in Travel 2017 Top Regions list. ↑
16. Source: “Cerro Sayhuite: Peru”. Geographic. Cited at: https://en.wikipedia.org/wiki/Sayhuite ↑
17. Source: Ministry of Foreign Commerce and Tourism. Main archaeological sites Archived 2009-11-22 at the Wayback Machine. Cited at: https://en.wikipedia.org/wiki/Sayhuite ↑
18. Source: Hemming, John (2010). Monuments of the Incas. Thames & Hudson. p. 184. ISBN 978-0500051634. Cited at: https://en.wikipedia.org/wiki/Sayhuite ↑
19. Explanation: A kancha is a rectangular enclosure in Inca architecture that typically consisted of four or more rectangular-shaped buildings built around a central courtyard or plaza. This basic design was used in the construction of many Inca cities and towns. Kanchas were often used for residential purposes, and each building within a kancha was usually occupied by a single family or group of people. The central courtyard of a kancha was often used for communal activities, such as festivals, religious ceremonies, or marketplaces. Kanchas were also used for other purposes, such as storage facilities or administrative centres. ↑
20. Source: https://www.guadalupe-school.org/wp-content/uploads/2020/06/chapter6_Inca.engineering-1.pdf ↑