Divali is a three-night festival, the last night of which is the first night of the waxing moon. The celebrations incorporate a number of mythic elements, many of which find colorful regional variation. As in any renewal rite, care is taken to cleanse and purify homes and shops, and people make certain to perform special ablutions in a ritual bath. The festival is most obviously characterized by the seemingly infinite number of oil lamps that are lit everywhere, as well as by the noise of exploding firecrackers that are said to frighten away evil spirits and to welcome the arrival of Laksmi, goddess of prosperity. In some regional practices the lamps are said to light the darkness for departed ancestors or to welcome the demon king Bali.