Among most scholars in the thriving field of evolutionary studies on religion, findings of burials are perceived as the first strong indicators of phenotypes evolving religiosity - that is: behavior towards supernatural agents (as ancestors, spirits or gods). Interestingly, these peculiar behaviors evolved not only in Homo sapiens, but also in Homo neanderthalensis.
Here, you are seeing a picture of the neanderthal grave in the Kebara Cave (Israel), which is dated to about 60.000 BC. Note the lack of the skull, which may hint to special rituals attributed to the head and secondary burials, as has been reported by many recent cultures of hunters and gatherers.
Although our scientific knowledge about the subject is still premature, the Smithsonian Museum of Natural History in Washington is showing a wonderful panorama of a Neanderthal burial, based on contemporary interpretations of a rich site in Southern France.
From an evolutionary perspective, the parallel, biocultural emergence of a specific behavior is another indicator for an adaptive process.