On the lake's southern shore stand the remains of Tiwanaku, a ceremonial centre that flourished for centuries before the Inca and that gave the region its most studied ritual architecture.
Its sunken court, lined with tenoned stone heads in a range of styles, its Gate of the Sun carved from a single block with a central staff-bearing figure surrounded by winged attendants, and its platform mounds have been excavated and argued over since the nineteenth century. The staff-bearing figure recurs across a very wide area of the Andes over a long period, which is one of the principal pieces of evidence for a shared religious iconography spanning several cultures.
Tiwanaku has also been used politically. Its stonework was appropriated for nationalist argument in the twentieth century, and the inauguration of Evo Morales as president of Bolivia in 2006 included a ceremony conducted there by Aymara ritual specialists, deliberately preceding the constitutional ceremony in La Paz.
The lake itself remains in ritual use. Aymara and Quechua communities on both shores make offerings to Pachamama and to the local mountain lords, burying or burning prepared bundles at the appropriate times of year, and the practice is ordinary rather than antiquarian. Underwater survey has recovered offerings deposited in the lake at ritual sites, including gold, shell and animal remains, showing the same practice running back well over a thousand years.