Reconstruction of a local Inca watchtower uncovered near Rancagua Inca watchtowers had square foundations, as opposed to the circular foundations of the qolqas or the rectangular foundations of the wasis. This square structure at the extreme north of the site was defensive, and positioned strategically. It was very high up, so difficult to fire missiles at but very easy to fire missiles from. As it was on a cliff top, it was impossible to climb. Furthermore, the occupant had Inca military technology and an arsenal of missiles at his disposal, traces of which have been found here.