The Inca capital Cusco and principal outlying towns of the Inca Empire were organised around a public plaza with a specially-constructed platform placed facing a designated sacred central space called the ushnu. This sacred space was marked by a vertical opening into the body of the earth into which liquid and other offerings were made.
The ushnu platform was therefore a kind of stage from which the Inca king and his lords could observe and preside over an annual round of seasonal festivals and ceremonial events.
These structures are carefully positioned on isolated mountain-tops 4,000–4,800 metres above sea level and represent some of the highest, dressed-stone architecture found anywhere in the Americas, and possibly in the world. These structures were clearly important in Inca political and sacred geography and had profound symbolic signifcance.
The sites were selected to command unsurpassed views of the snow-capped mountain peaks, worshipped as wamanis, or mountain deities, by the local communities. In this way local deities were incorporated into the overarching Inca state religion. The Incas used the platforms as potent symbols of religious and political authority. They served as an innovative and powerful new instrument of statecraft in order both to defne and proclaim their growing imperial hegemony.