The Machu Picchu citadel is in the picture. It was built by Inca civilization and became the main icon of the Incan culture. The construction is widely considered the main known example of the classical Incan architecture. It was constructed as an estate for the emperor Pachacuti. Finished in 1450, the estate was left by Inca people a century later. The object remained unknown even after the time of the Spanish Conquest, as well as for the rest of the world. Only in 1911 Hiram Bingham became the first explorer to bring the citadel to international attention. That made him a prominent and well-known historian and became his main achievement.

More Info: en.wikipedia.org