A sweat lodge is an important aspect of many native cultures along North America, Siberia and North Europe whose religious beliefs depend on the shaman. It is a place of ritual purification and mystical insight through a vision quest, where the shaman performs prayers and songs in a sauna-like environment (the word 'sauna' is itself of Finnish origin and goes back to the shamanic heritage of Siberia). Anthropologists and psychoanalysts have observed and studied the fact that modern science-fiction very often reflects ancient epic structures (see Bibliography).