Machu Picchu: Architecture, Function, and the Inca World
Machu Picchu, the Inca settlement on a ridge between two mountain peaks 2,430 metres above sea level in the Peruvian Andes, is the best-preserved site of the Inca civilisation and one of the most visited archaeological sites in the world. It has been a UNESCO World Heritage Site since 1983 and was designated a Wonder of the World in a 2007 popular poll. Beyond its photogenic quality, Machu Picchu is archaeologically significant as the most complete surviving example of Inca urban planning, architecture, and agricultural engineering — preserved in a condition unparalleled anywhere else in the Inca world because it was abandoned before Spanish colonial disruption.
The Setting
The site is located in the cloud forest zone of the eastern Andes at 2,430 metres elevation, on a saddle between the peaks of Machu Picchu ("Old Peak") to the south and Huayna Picchu ("Young Peak") to the north. The Urubamba River curves around the base of the ridge in an almost complete loop, creating a natural moat on three sides. The setting is intentional: Inca sacred geography accorded special significance to mountain peaks (apus), water sources, and the meeting of landscape features. The entire site was carefully positioned within this sacred topography.
The altitude means that Machu Picchu is often cloud-covered, particularly in the wet season (October to April). The best visibility is generally in the dry season (May to September), and particularly in the early morning before clouds build from the valley.
Who Built It and When
Machu Picchu was built on the orders of the Inca emperor Pachacuti (also Pachacutec), who ruled from 1438 to 1471 CE and transformed the Inca state from a local chiefdom into an imperial power spanning 4,000 km of the Andean coast. Radiocarbon dating of human remains from the site, combined with analysis of associated ceramics, confirms construction and occupation in the mid-fifteenth to early sixteenth centuries. The site was probably occupied for less than 100 years before being abandoned around 1530–1540 CE, shortly before or during the Spanish conquest.
The primary function of Machu Picchu was as a royal estate and ceremonial centre for Pachacuti. The Inca practiced a form of split inheritance in which the emperor's personal wealth, including land and palaces, passed not to his successor but to his descendants (his panaca or royal lineage group), who maintained his mummy and memory and continued to use his properties. Machu Picchu was the Pachacuti panaca's estate, maintained by a resident population of approximately 500 to 1,000 people (primarily women dedicated to religious and administrative service) between the emperor's seasonal visits.
The Architecture
Machu Picchu is divided into two main zones by a broad agricultural terrace: an urban sector and an agricultural sector. The urban sector contains the Royal Palace (the most finely finished residential complex, with trapezoidal niches and double-jambed doorways indicating high status), the Temple of the Sun (a D-shaped tower built on a natural granite outcrop, with windows aligned to solar events), the Temple of the Three Windows, and the Intihuatana — a carved stone pillar whose name means "hitching post of the sun" and which may have functioned as an astronomical instrument.
The construction technique — dry-stone masonry of precisely fitted irregular blocks with no mortar — is the defining Inca architectural style. The fitting is so precise that a knife blade cannot be inserted between blocks. The stone (primarily granite) was quarried from the ridge itself and shaped using stone and bronze tools; the blocks were moved using log rollers and ramps. The seismic engineering of Inca masonry is now recognised as sophisticated: the irregular polygonal fitting means that during an earthquake, the blocks move slightly and resettle without catastrophic collapse.
The terracing (andenes) on the steep slopes below and around the settlement served both agricultural and stabilisation functions. The terraces, filled with imported topsoil, grew maize, potatoes, quinoa, and other crops. An elaborate drainage system — channels, drains, and a series of seventeen fountains drawing water from a spring above the site — managed water flow across the terraced landscape.
Hiram Bingham and the "Discovery"
Machu Picchu entered international awareness through the American explorer and academic Hiram Bingham, who was guided to the site on 24 July 1911 by a local farmer named Melchor Arteaga and a young boy named Pablito Richarte. The claim that Bingham "discovered" the site is inaccurate: the terraces were being farmed by local families (the Alvarez family appears in Bingham's own photographs); the site was known to local people and to Peruvian landowners in the area. What Bingham did was introduce the site to international academic and popular audiences, conduct the first systematic excavation, and photograph it extensively.
Bingham removed approximately 40,000 artefacts and human remains to Yale University under a loan agreement with the Peruvian government. After decades of diplomatic dispute, Yale University agreed in 2010 to return the collection to Peru, where it is now displayed in a purpose-built museum in Cusco.
The Skeletal Evidence
Osteological analysis of the human remains from Machu Picchu has revised earlier claims (made by Bingham on limited evidence) that the site was populated primarily by women. More thorough analysis of the skeletal collection, completed at Yale in the 2000s, found a roughly equal sex ratio. Isotope analysis of the bones indicates that the resident population came from many different parts of the Inca empire — not just the Cusco heartland — consistent with the yana and acllas (service and selected women) who staffed royal estates.
Visiting Machu Picchu
The site is reached by train from Cusco or Ollantaytambo to Aguas Calientes (the nearest town), then by bus up a switchback road to the site entrance. Entry requires advance booking through the official ticketing system (machupicchu.gob.pe); daily visitor limits are enforced. The Sun Gate (Inti Punku), reached by a 90-minute walk along the Inca Trail, provides the classic approach view. Early entry tickets allow the site to be experienced before the majority of visitors arrive. The hike up Huayna Picchu requires a separate timed ticket with very limited capacity; the Mountain of Machu Picchu hike has fewer restrictions and better overall views.