Fossil teeth found at Grotte Mandrin, France. At left is the tooth of a Homo sapiens child, that dates to 54,000 years ago and at right is the tooth of a Neanderthal child, that dates to around 52,000 years old. Fossils from this cave have shown that modern humans (Homo sapiens) arrived in Western Europe earlier than thought and co-existed with Neanderthals for over 15,000 years before Neanderthals went extinct. It was previously thought that the arrival of modern humans quickly lead to the extinction of the Neanderthals. Fossils of modern humans found at the site date to 54,000 years ago, 12,000 years before it was thought they had reached Europe. The modern humans occupied the site for a couple of thousand years, before leaving it unoccupied. Neanderthals then occupied the site for several thousand years, until modern humans returned 44,000 years ago. Neanderthals went extinct around 40,000 years ago.