The Incas started building the "estate" around AD 1400, but abandoned it as an official site for the Inca rulers a century later at the time of the Spanish Conquest. Although known locally, it was unknown to the outside world before being brought to international attention in 1911 by the American historian Hiran Bingham. Since then, Machu Picchu has become an important tourist attraction. Most of the outlying buildings have been reconstructed in order to give tourists a better idea of what the structures originally looked like. By 1976, thirty percent of Machu Picchu had been restored. The restoration work continues to this day.
Since the site was never 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 2007, Machu Picchu was voted one of the New Sever Wonders of the Modern World in a worldwide Internet poll.