What is Machu Picchu?

High in the mountains of Peru, hidden in clouds and wrapped in mist, sits a city of stone. It was built so long ago that the people who made it never wrote down its story. For four hundred years, the jungle kept it secret. This is Machu Picchu — and finding it was like discovering a lost world.
The Inca people built Machu Picchu around the year 1450. They ruled a vast empire along the spine of South America's tallest mountains — the Andes. The Inca were master builders. They cut massive stones so precisely that they fit together like puzzle pieces, without any mortar or cement. Some of those stones weigh as much as a school bus.
