Puca-Pucara would deal about a military building made up by overlapping terraces, interior squares, aqueducts, watchtowers, high walls and staircases. However, Its presence along the road may also indicate that it was a wayside inn, though its structure does not belong to the standard outlining that characterizes those buildings along the Inca trails. On this possibility, there is a version that says the Inca accommodated there his numerous delegation each time he decided to visit the Tambomachay baths.
The site occupies another typical rocky place standing out in the Sacsayhuamán plain. Towards the western side, it shows a facade on a free area like a small square. On the opposite site, there is a medium size building, which main characteristic is its strategic location since it controls the whole surrounding territory.
It was built with three walls of irregular plant that set three levels for each site.
The first wall was outlined to be winding so as to carefully avoid cutting the prominent rocks. Towards the north and behind the outside wall, there are six rooms of different sizes arranged in such an irregular way so as not to touch the stones forming the wall. Towards the west, there is a high trapezoid square, which is accessed by a staircase. Buildings on both sides surrounded the square. The nine rooms of regular outline in this open area do not seem to belong to a fortified environment.
A second wall surrounds the central elevation. Between this and the first, there are wide cultivation terraces that spread all over towards the south and the east. Behind the second wall, there are three atypical rooms for the Inca architecture since two of them lack of a rectangular plant, it is trapezoidal. The third wall surrounds the top and there are no traces left of its buildings.