Sillustani is a pre-Incan burial ground on the shores of Lake Umayo
. The tombs, which are built above ground in tower-like structures called chullpas, are the vestiges of the Colla people, Aymara who were conquered by the Inca in the 15th century. The structures housed the remains of complete family groups, although they were probably limited to nobility. Many of the tombs have been dynamited by grave robbers, while others were left unfinished.
Ancestor worship and kinship were integral parts of Aymara culture, and the huge chullpas or "chupa" at Sillustani were built to house the Aymara elite of the immediate pre-Inca and Inca period. The word was used in the 19th century and comes from the Dictionary of Ludovico Bertonio (1612). Bertonio referred to the basket burials of the semi-nomadic pastoralists as "chulpas" and actually referred to stone towers as "uta Amaya" "houses of the soul".
However, the term "chullpa" remains used today for the towers. Many of the chullpas at Sillustani show pre-Inca characteristics that were later redressed with Inca stone blocks. Similar chullpas are found throughout the entire south Central Andes with the above ground burial styles going back at least to mature Tiwanaku (ca AD 500-950).
The insides of the tombs were built to hold entire groups of people, most likely extended families of the Aymara elite. Corpses were not intentionally mummified, but in the dry environment created by the closed tomb, they survived for centuries.
The architecture of the site is often considered more complex than typical Incan architecture. In contrast with the Inca, who used stones of varying shapes, the Colla used even rectangular edges. While chullpas are not unique to Sillustani and are found across the Altiplano, this site is considered the best and most preserved example of them.