The Incas built the city on a mountain ridge, 2430m above sea level. They lived there between 1200 and 1450 AD. Other people lived there before about 650 AD.The Incas built houses, fields and temples by cutting the rock on the mountain so it was flat. They built an observatory to look at the stars.
When the Spanish invaded Peru, the Incas left Machu Picchu. Nobody knows for sure why they did that, but some think it was because Of deaseases from Europe. The city was left unfinished, most likely due to the Spanish invasion and/or a civil war between the ruling rival Inca brothers named Huascar and Atahualpa. The Spanish never found Machu Picchu or the lost city during their occupation.
Machu Picchu is very difficult to get to because it is so high in the mountains. It has only one way in and a stone wall to protect it. Most people on Earth did not know it was there until a Yale graduate named Hiram Bingham rediscovered it in 1911. He heard rumours of a hidden city which was already known to the native Peruvians, who guided him there. He led a restoration project that was partly funded by the National Geographic Society. Bingham made a deal with the government to take artifacts to the Peabody Museum for study. Peru is still trying to have those artifacts returned to them.
