Located in southern Peru, this ruined city lies on top of a mountain that’s only accessible by train or a four-day trek. Rediscovered by Hiram Bingham in 1911, it was an important cultural center for the Inca civilization but was abandoned when the Spanish invaded the region. (It is famously referred to as the “Lost City of the Incas,” though that is actually Vilcabamba). The location was made a UNESCO World Heritage site in 1983, and it was named one of the New Seven Wonders of the World in 2007. Concerns over growing numbers of tourists have led to limitations on how many people can enter the site, though only by a fraction of what is necessary. Hopefully they will limit it even more so this site can last for hundreds of years more.