Sillustani is a pre-Incan burial ground on the shore of Lake Umayo, near Puno. The tombs, which are built in tower-like structures called chullpas, are vestiges of the Collas, people part of the Aymara culture conquered by the Inca in the early 1400īs. The structures housed the remains of family groups, and were probably limited to nobility. Many of the tombs have been looted by grave robbers. Worshiping their ancestors was very important for the Aymaras, and the chullpas were built to emphasize the connection between life and death. The tombs were shaped like a woman's uterus, and corpses were mummified in a fetal position, since Aymaras believed in re-incarnation. The only openings of the buildings face east, since they believed that at sunrise the god Sun was re-born. The architecture is considered more complex than Incan architecture. While the Incas used stones of varying shapes, the Colla used even rectangular edges. While chullpas are not unique to Sillustani and are found across the Andes, the ones at this site are considered the best preserved.