One of the most important and most visited PreColumbian sites in the Americas, an outstanding symbol of
Peruvian national pride and Inca civilisation. The ruins are a uniquely sited royal winter retreat, religious
sanctuary and mausoleum of the Inca rulers from Cuzco built around the middle 15th century, superbly
constructed and integrated with a spectacularly beautiful landscape. Its sheltered and remote location has
preserved a very rich endemic and relict flora and fauna, including the rare spectacled bear.
Threats to the site: Inadequate governance and institutional coordination, landslides, fire, heavy tourist
pressures, and the unplanned, unsafe and unsanitary development of Machu Picchu village.
Machu Picchu stands 2,430 m above sea-level, in the middle of a tropical mountain forest, in an extraordinarily beautiful setting. It was probably the most amazing urban creation of the Inca Empire at its height; its giant walls, terraces and ramps seem as if they have been cut naturally in the continuous rock escarpments. The natural setting, on the eastern slopes of the Andes, encompasses the upper Amazon basin with its rich diversity of flora and fauna.
The site lies between the selva alta and yunga zones of the Andean plateau in the steep and highly dissected topography of the eastern high Andes, rising from a deep gorge to glacier-bearing mountains. The ruins rise just above cloud forest on the flattened top of a narrow steep-sided ridge which rises within but some 650m above a meander of the Rio Urubamba (Rio Vilcanoto) canyon. The spectacular site is on the northern end of the Cordillera de Vilcanoto facing the Cordillera de Vilcabamba across the valley which rise in the nearby tutelary mountain of Cerro Salccantay to 6,271 meters, and lies in the shelter of these peaks. The ridge forms a saddle at 2,430m between a humpbacked mountain (Machu Picchu, 2,795m) and a pinnacle, Huayna Picchu (2,667m) which overlook the ruins. The remaining buildings are single storey and built of a local white granite. They comprise the upper ceremonial buildings - palace, temples and tombs - separated by a long plaza from the peoples’ housing and agricultural terraces below. Geologically the area is a complex of intrusive lavas and metamorphic rocks. Ordovician schists, slates and quartzites lie under a layer of Cretaceo-Quaternary marine sedimentary rocks. The area is prone to earthquakes and a fault line crosses the site. There are hot springs nearby at Aguas Calientes. Most of the soils are acid, poorly developed and shallow. In the valleys below, colluvial and alluvial soils and rocky detritus predominate. The hillsides were carefully terraced by the Incas to conserve the thin soil, but under heavy rains the slopes are liable to landslides and erosion, especially on the steep backslope of the ridge. The Urubamba river, which is an upper tributary of the Amazon, flows below the site in a canyon, but its alluvial basin as far as Quillabamba to the north, the ‘Sacred Valley of the Inca’ is an almost continuous band of arable and pastoral farmland fed by many side valleys and flanked by innumerable irrigated terraces, forming one of the most productive areas in the Andes. From Machu Picchu the ’Sacred Road of the Incas’ or Inca Trail across the mountains links the site with the old Inca capital of Cuzco 75 km up the valley which is also reached by road and rail in the valley.
CLIMATE
The site is sheltered by the snow-capped mountain ranges of Salccantay to the south and the peak of La Verónica to the east. The climate on the mountain is humid but temperate. At 2,500m the average annual temperatures range between 12°C and 15°C with annual rainfall averaging 1,950 mm and frequent mist. On the high paramo the diurnal variation in temperature exceeds the fairly constant annual range. The agricultural valley below is warmer: the temperature there averages 16°C and the rainfall ranges between 1,850mm and 3,000mm. The wet season lasts from October to April. The winter, between May and September is dry and is the season for forest fires in the lower forest and the paramo, though the cloud forest between the two remains moist.
VEGETATION
The site is on the margin between the Andean and Amazonian ecosystems, possessing elements of both. Because of the altitudinal range, irregular terrain and long alteration by man, it possesses a great diversity of habitats within a short distance: riverine vegetation, humid and very humid low montane subtropical forests, humid evergreen and quasi-cloud forests, cultivated fields, terraces which have reverted to grass and secondary scrub or woodland, with above the ruins, bamboo, Polylepis thickets and paramo grasslands. Its montane forests, though partially degraded, contain one of the richest and most threatened of all floras. Shoobridge et al. (2004), following Holdridge, give the following nine life zones:
