The discovery of ancient bones carved into tubes in the mountains of Peru led researchers to conduct chemical analyses. The the substances were used as part of a hierarchical class system, as well as for their hallucinogenic impact. Researchers discovered that pre-Inca stone structures from the mountains of Peru had secret rooms accessible to only the most exclusive in society. In those rooms, they found bones carved into tubes used as psychedelic paraphernalia—part of a ritualistic experience in which special leaders smoked psychoactive plants. The Chavin have been linked to earlier more egalitarian societies, and the mountain-spanning empires ruled by elites that came later.