Machu Picchu is a citadel of the Inca civilization, located in the Cusco region of southern Peru, with an altitude of 2,430 meters in the eastern Cordillera mountain range. It was constructed as an estate for the Incan emperor, Pachacuti, in the 15th century and was abandoned in the 16th century during the Spanish conquest.

In 2021, new AMS radiocarbon-dating research suggests that Machu Picchu was occupied from A.D. 1420 to A.D. 1532, while Emperor Pachacuti's rise to power was in A.D. 1438. (Burger et al., 2021)

Machu Picchu was originally called Picchu, or more likely Huayna Picchu, as indigenous people mentioned it when the Spanish conquerors entered the area in the late 1500s. (Gonzales and Bauer, 2021)

As the surrounding jungle grew dense during the centuries, Machu Picchu became less known to non-locals, but there is evidence that Augusto Berns and J. M. von Hassel visited in 1874 and 1867, respectively.

In 1911, Hiram Bingham was traveling around the area in search of the capital of the Inca. He was guided to the area between Machu Picchu and Huayna Picchu, which can be interpreted as “old mountain” and “young mountain” in the Quechua language, by a local villager, Melchor Arteaga. He started to associate the place with the name Machu Picchu and brought it to international attention. (Bingham, 2003)

Hiram Bingham brought thousands of artifacts from Machu Picchu to Yale University in the 1910s, including pottery shards, ceramic vessels, etc. and in the 2010s, Yale University agreed to return them. (CNN, 2010)

As a estate of Emperor Pachacuti, about 750 people were estimated to be living in Machu Picchu. Most of them appeared to be religious staff and specialized workers serving the ruler.

According to chemical markers and osteological markers on the human remains, residents in Machu Picchu were immigrants from various areas of Peru. Chemical densities in these remains indicate the short-term diet for some people included less fish and more corn, so they were probably from coastal regions and then moved to Machu Picchu, where corn was consumed in larger quantities. (Turner, Kingston and Armelagos, 2010)

Most of the animal remains being found belong to llamas and alpacas, which were probably not native to Machu Picchu either because they lived in areas with higher altitudes. In addition, guinea pigs and six dogs were recovered at the site, implying their roles in funerary rituals and companionship. (Burger and Salazar, 2004)

Machu Picchu has man-made terraces to provide sufficient drainage, maintain soil fertility, and protect the mountain from erosion because the area received rainfall that was excessive for agriculture. The bottom layer of the terraces consisted of large stones. After a layer of loose gravel and a layer of mixed sand and gravel, the top was covered with rich soil that was probably transferred from the valley. (Brown, 2001)

Machu Picchu has many structures carefully constructed for ritual and astronomical purposes, such as the Temple of the Sun, the Intihuatana stone which was set to point at the sun directly during the winter solstice (Amao, 2012), and Intimachay, an observatory at the entrance of a cave that only allowed light for a brief period in December (Dearborn, Schreiber and White, 1987).

Many of the buildings were made with polished stone regular shapes with the ashlar technique, where stone blocks were cut to fit together tightly without mortar. (Wright et al., 2022) Other techniques were also used to stabilize the walls, such as trapezoidal doors and windows, rounded corners, and offset blocks.

Since Machu Picchu’s rediscovery in the 1910s, it has become a popular tourist attraction. It was designated as a World Heritage Site by UNESCO in 1983 and was listed as one of the New 7 Wonders of the World by over one hundred million votes in 2007 (Creating Global Memory, 2007).