Ritual disposal of human remains. The practice is often intended to facilitate the deceased's entry into the afterworld. Grave burial dates back at least 125,000 years. Types of graves range from trenches to large burial mounds to great stone tombs such as pyramids. Caves have also long been used for the deade.g., in ancient Hebrew burials, the sepulchral caves (rock temples) of western India and Sri Lanka, and the Dogon cliff burial sites. Water burial, such as occurred among the Vikings, has also been common. Cremation and the scattering of ashes on water is widely practiced, especially in Asia; in India the remains of the deceased are thrown into the sacred Ganges River. Some peoples (American Indian groups, Parsis, etc.) employ exposure to the elements to dispose of their dead. Among many peoples, the first burial is followed by a second, after an interval that often coincides with the duration of bodily decomposition. This reflects a concept of death as slow passage from the society of the living to that of the dead. Jewish custom requires speedy burial; a prayer known as the Kaddish is recited at the graveside, and a gravestone is normally erected a year after burial. Christian burials are often preceded by a wake, a watch held over the deceased's body and sometimes accompanied by festivity. Bodies of Muslims are laid on their right side and facing Mecca.