Sun Dance, a religious festival once common among North American Plains Indians. Its general purpose was to do homage to the deities, sometimes to gain a specific benefit but more usually as an annual ritual at the start of the hunting season. Typically, it lasted from four to eight days and included, besides ceremonial dancing, purification in sweatlodges (similar to saunas), erection of altars, and, in some tribes, self-torture. Because of the torture, the U.S. Department of the Interior prohibited the festival in 1904; it removed the ban in 1935. Various tribes have resumed the Sun Dance.