High in the Andes mountains, the Inca thrived for hundreds of years before the arrival of the Europeans.  On July 24, 1911, Yale history lecturer Hiram Bingham III laid eyes upon Machu Picchu, a forgotten city in the clouds.  Almost a century later, the landmark received the honor of being named one of the New Seven Wonders of the World. Bingham, working as part of the Yale Peruvian Expedition and later with aid from the National Geographic Society, began excavating the ruins – recovering and removing thousands of objects without Peruvian consent.

Standing 2,430 m above sea level, in the midst of a tropical mountain forest in an extraordinarily beautiful setting, Machu Picchu 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.  Machu Picchu covers 32,500 ha in some of the scenically most attractive mountainous territory of the Peruvian Andes. Machu Picchu is one of the most important cultural sites in Latin America; the stonework of the site remains as one of the world’s great examples of the use of a natural raw material to provide outstanding architecture which is totally appropriate to the surroundings. The surrounding valleys have been cultivated continuously for well over 1,000 years, providing one of the world’s greatest examples of a productive man-land relationship. Machu Picchu also provides a secure habitat for several endangered species, notably the spectacled bear, one of the most interesting species in the area.

Though the reasons behind the Inca abandonment are unknown, disease is often theorized as the primary cause.  Believing the European influx of smallpox to be too much for the tribe to bear, it seems likely the diminishing numbers of natives were unable to maintain the vast site.  According to the best estimates, the Inca left Machu Picchu in the 1570s, hardly more than a century after the site was completed.

Reference:

http://www.mapsofworld.com/on-this-day/july-24-1911-ce-machu-picchu-is-found-again

http://whc.unesco.org/en/list/274