Cusco (also Cuzco, Qosqo, or Qusqu) is a city in southeastern Peru, near the Urubamba Valley (Sacred Valley) of the Andes mountain range. It is the capital of the Cusco Region as well as the Cusco Province. The city has a population of about 300,000, triple the population it contained just 20 years ago. The altitude of the city is around 3,500m (11,500 feet). The historic capital of the sun-worshipping Inca empire, it has been found in 2006 to be the spot on Earth with the highest UV level.

Cusco was the capital of Inca Empire. The city was planned to be shaped like a puma. The city had two sectors: the urin and hanan, which were further divided to each encompass two of the four provinces, Chinchasuyu (NW), Antisuyu (NE), Cuntisuyu (SW), and Collasuyu (SE). A road led from each of these quarters to the corresponding quarter of the empire. Each local leader was required to build a house in the city and live part of the year in Cusco, but only in the quarter of Cusco that corresponded to the quarter of the empire he had territory in. After Pachacuti, when an Inca died his title went to one son and his property was given to a corporation controlled by his other relatives, so each title holder had to build a new house and add new lands to the empire, in order to own any home and the land his family needed to maintain it after his death. Andean Indians still abandon their homes and build new ones when they marry, even if no one remains in the house.
According to Inca legend, the city was built by Sapa Inca Pachacuti, the man who transformed the Kingdom of Cusco from a sleepy city-state into the vast empire of Tahuantinsuyu. But archaeological evidence points to a slower, more organic growth of the city beginning before Pachacuti. There was however a city plan, and two rivers were channeled around the city