Neanderthals lived on Earth thousands of years ago. Recent research shows that they used their fingers to leave markings on the insides of cave walls. The engravings, which include dots, stripes, and other symbols, are believed to be one of the oldest forms of art.

Neanderthals would have just swept their fingers over the once soft cave walls in La Roche Cotard in France to make the artwork. It’s a technique called finger-fluting, but no one is sure what the marks mean, or what they do. The Neanderthal art is thought to be one of the oldest known European art forms too. The art was made on eight separate panels on the upper parts of the cave walls. Most of the traces seem to be made by fingers laid flat, a few of them look like they were drawn on the edge of the finger.

Research says that the entrance to the cave was sealed by sediments a couple thousand years ago. The researchers say that this would have been the last time humans or animals could have gone into the cave, before it was rediscovered in the 20th century. Only Neanderthals could have made the engravings.

The cave entrance was closed before Homo sapiens were known to the area. The artwork is probably around 75,000 years old.