From The National Geographic:
One of three successful candidates from Latin America, Machu Picchu is a 15th-century mountain settlement in the Amazon region of Peru.
The ruined city is among the best known remnants of the Inca civilization, which flourished in the Andes region of western South America. The city is thought to have been abandoned following an outbreak of deadly smallpox, a disease introduced in the 1500s by invading Spanish forces.
More here. (For Ga via Akbi).