Machu Picchu is a 15th-century Inca site located 2,430 metres (7,970 ft) above sea level. Machu Picchu is located in the Cusco Region of Peru, South America. It is situated on a mountain ridge above the Urubamba Valley in Peru, which is 80 kilometres (50 mi) northwest of Cusco and through which the Urubamba River flows.

Since the site was not known to the Spanish during their conquest, it is highly significant as a relatively intact cultural site. Machu Picchu was declared a Peruvian Historical Sanctuary in 1981 and a UNESCO World Heritage Site in 1983. In 2007, Machu Picchu was voted one of the New Seven Wonders of the World in a worldwide Internet poll.

Somewhere safe to hide from the Spaniards

it was a city

No one knows for certain. There is no documentation.