Pucapucara on the road from Cusco to the Sacred Valley is often called the Red Fort.
But it’s more likely it was a customs house for traders entering the imperial capital.
From the valley below it presents a sheer stonewall, but from road on the other side it appears to be a more open building with few defenses.
The walls include examples of the Inca’s distinctive trapezoidal niches also found at Machu Picchu.
The building includes a number of rectangular structures that were most likely warehouses.
It also includes channels that fed running water throughout the complex.