Machu Picchu The lost city of the Incas was initially thought to have been brought to the attention of the modern world by an American explorer, Hiram Bingham, in 1911, after laying undiscovered since the fall of the Incan Empire in the 1530s. However, a research team recently suggested it was looted more than 40 years previously by a German adventurer with the help of the Peruvian government. The spectacular terraces at the site are now a hugely popular tourist attraction but it remains unclear exactly why the city was built in such a location. The most popular of the current theories concern sacrificial virgins and astronomical alignment. - Eric Buckley