The Sacred Valley of the Incas or Urubamba Valley is a valley in the Andes of Peru, close to the Inca capital of Cusco and below the ancient sacred city of Machu Picchu. In colonial documents it is referred to as the "Valley of Yucay", according to recent researches it encompasses the heartland of the Inca Empire. The valley is generally understood to include everything between Calca and Lamay, Písac and Ollantaytambo, it has been formed by the Urubamba River, also known as Vilcanota River or Wilcamayu. The latter means in Quechua, the still-spoken lingua franca of the Inca Empire, the Sacred River. It is fed by numerous rivers which descend through adjoining valleys and gorges and contains numerous archaeological remains and villages. The valley was appreciated by the Incas due to its special geographical and climatic qualities. It was one of the empire's main points for the extraction of natural wealth, and one of the most important areas for maize production in Peru northward from Pisac. The early Incas may have come from Wimpillay as their mummies have been discovered there. Large-scale maize production started around 1400 as Inca urban agriculture.
Information based on http://en.wikipedia.org/wiki/Sacred_valley