Today in 1911, an American archaeologist named Hiram Bingham first discovered Machu Picchu and brought it to the attention of the English-speaking world.
Machu Picchu, which was built to the northwest of Cuzco, was probably a summer home for Incan leaders. It was kept a secret from the world at large, known only to locals. Rumors about a "lost city" did circulate, though, and Bingham led an expedition to the area to investigate.
Bingham and his small coterie of fellow explorers embarked into the countryside in July of 1911. They traveled from Cuzco into the Urubamba Valley, where they met a farmer who told them about ruins at the top of a mountain named Machu Picchu. The Quechua name translates as "Old Peak."
Bingham's team reached the mountain the following day, July 24. Getting to the mountain's ridge was a long, hard slog through inclement weather, but they made it. There, they encountered a group of natives who guided them the rest of the way to the top of the mountain. Bingham, following the lead of an 11-year-old boy, finally reached the ruins.
Bingham published an account of the expedition in a book that became an instant hit. The book precipitated a flood of tourism to the area.
Today, Machu Picchu hosts over 400,000 tourists per year. It is the most familiar icon of the Inca, constructed sometime around 1450 A.D. The Inca abandoned the site during the Spanish Conquest during the following century.
Machu Picchu was constructed in the classical Inca style. It consists of three main structures - the Inti Watana, the Temple of the Sun and the Room of the Three Windows. The peripheral buildings have been reconstructed for the benefit of tourists. A full 30% of Machu Picchu had been reconstructed by 1976.
Machu Picchu is Peru's most-visited tourist attraction. It's also a major source of revenue. The Peruvian government greenlit a project in the 90's to build a cable car and luxury tourist accommodations for the site, despite fervent protest from Peruvian citizens and scientists who warned that the increased traffic would damage the ruins.
Machu Picchu is now on the UNESCO List of World Heritage in Danger. It is also a somewhat dangerous tourist destination, with multiple deaths occurring from landslides, earthquakes and injury from decaying buildings.
In recent years, a trend of "nude tourism" has cropped up at Machu Picchu. People have been arrested for posing nude in the ruins and also streaking.