Pisac is perhaps best known for its Incan ruins, which lie atop a hill at the entrance to the valley. The ruins are separated along the ridge into four groups: Pisaqa, Intihuatana, Q'allaqasa, and Kinchiracay. Intihuatana, a volcanic outcrop carved into a "hitching post" for the Sun (or Inti), is the focus of the complex. The angles of its base suggest that it served some astronomical function. The colonial town of Pisac lies down in the valley and is very known for its local market.