These mysterious ancient burial towers were built by the Colla people who used brick-like rectangular edges, in contrast with the Inca who used stones of varying shapes.
The Colla, who were later incorporated into the Inca empire, constructed the towers to bury their nobility. The carefully carved stones are adorned with complicated carvings, some of which project out from the surface of the piece.
At one end of the hill stands the tallest of the towers at 40 feet (12 m). From here you can enjoy views of Puno; on the other side it's possible to see smaller towers set against the backdrop of Lake Umayo.
Unfortunately, many of the tombs have been pillaged by grave robbers, while others were left unfinished by the original builders.
AncientPages.com
References: Go2Peru, El Comercio