In his book, Becoming Human, Ian Tattersall says,

The Neanderthals had occasionally practiced burial of dead, but among the Cro-Magnons we see for the first time evidence of regular and elaborate burial, with hints of ritual and belief in an afterlife.

The most striking example of Cro-Magnon burial comes from the 28-kyr-old site of Sungir, in Russia, where two young individuals and a sixty-year-old male (no previous human had ever been known to survive to such an age) were interred with an astonishing material richness. Each of the deceased was dressed in clothing onto which more than three thousand ivory beads had been sewn; and experiments have shown that each bead had taken an hour to make. They also wore carved pendants, bracelets, and shell necklaces. The juveniles, buried head to head, were flanked by two mammoth tusks over two yards long. . . . Also found at Sungir were numerous bone tools and carved objects, including wheel-like forms and a small ivory horse decorated with a regular pattern of tiny holes. The elaborate interments at Sungir are only the most dramatic example of many; and taken together, these Cro-Magnon burials tell us a great deal about the people who carried them out.

First, in all human societies known to practice it, burial of the dead with grave goods (and the ritual invariably associated with placing such objects in the grave) indicates a belief in an afterlife: the goods are there because they will be useful to the deceased in the future. Grave goods need not necessarily be everyday items, although everything found at Sungir might have been, since personal adornment seems to be a basic human urge that was expressed by the Cro-Magnons to its fullest. But whether or not some of the Sungir artifacts were made specifically to be used in burial, what is certain is that the knowledge of inevitable death and spiritual awareness are closely linked, and in Cro-Magnon burial there is abundant inferential evidence for both. It is here that we have the most ancient incontrovertible evidence for the existence of religious experience. (from Becoming Human: Evolution and Human Uniqueness, by Ian Tattersall.)