Located in the Bolivian highlands, Puma Punku is a field of stone ruins scattered with giant, finely carved blocks.
In assembling the walls of Pumapunku, each stone was finely cut to interlock with the surrounding stones and the blocks fit together like a puzzle, forming load-bearing joints without the use of mortar.
One common engineering technique involves cutting the top of the lower stone at a certain angle, and placing another stone on top of it which was cut at the same angle. The precision with which these angles have been utilized to create flush joints is indicative of a highly sophisticated knowledge of stone-cutting and a thorough understanding of descriptive geometry.
Many of the joints are so precise that not even a razor blade will fit between the stones.Much of the masonry is characterized by accurately cut rectilinear blocks of such uniformity that they could be interchanged for one another while maintaining a level surface and even joints.
Ancient alien theorists have hypothesized that extraterrestrials with advanced engineering techniques created the site or advised the people who built it.