Machu Picchu was built by the Inca – the ruler of the Quechua people – in the 15th century, shortly before the Spanish arrived. It was never occupied by the Spanish, but was abandoned as the Spanish took control of Cusco and the surrounding area. However, the first European to visit the site did not do so until 1911. In 1983 it became a World Heritage Site, and in 2007 was voted one of the New Seven Wonders of the World.
Machu Picchu is just an amazing place to visit. It is built at the top of a Mountain 2,430m above sea level and over 450m above the Urubamba River (see my Blog about the Sacred Valley). In places the edge of the site drops away vertically with cliffs falling right down into the river valley! It is no surprise that the Spanish never found the site. There are lots of ideas about why it was built but it would appear to combine – a summer retreat for the Inca; a religious site with temples to the Sun; an agricultural research centre; and an astronomical research centre.
The following slide show might give you some idea of the wonder of the place, but it is only a partial view.