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. Most mummy bundles indicate burial in a fetal position. Some of the tombs also have various animal shapes carved into the stone. The only openings to the buildings face east, where it was believed the Sun was reborn by Mother Earth each day. [Wikipedia]