Sillustani is a pre-Incan burial ground on the shores of Lake Titicaca near Puno. 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 1400s. 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 chullpas were built to emphasize the connection between life and death. The insides of the tombs were shaped like a woman's uterus, and corpses were mummified in a fetal position to recreate their birth. Some of the tombs also have lizards carved into the stone. Because they could regrow their tails, lizards were considered a symbol of life. The only openings to the buildings face east, where it was believed the Sun was reborn by Mother Earth each day.