This is a wall engraving from Abri Castanet, a shallow cave in southern France's Vezere valley. It's the oldest known cave etching, probably dating back around 37,000 years—and the researchers claim it depicts female genitalia.
Since 1994, a team of researchers has moved its focus from the other oldest inhabited caves in France, at Chauvet-Pont-d'Arc. Instead, the team has settled down to work in Abri Castanet, and has found evidence of occupation dating back as far as 40,000 years.
Most recently, they discovered a portion of the cave that had been previously unexplored. They found a bunch of bones of reindeer and other animals, and when they carbon dated them, they all clustered in an age range dating them back 36,000 to 37,000 years.
They also found these engravings—and so with, with some certainty, are able to claim that they are the oldest of their kind, at around 37,000 years old, a finding they report in the Proceedings of the National Academy of Science. While it may sound tenuous, according to Science numerous academics agree that these are indeed the oldest engravings yet to be found. There are some older paintings we know of, but not engravings.