Shocking new insights into the demise of modern humans' sister species, the Neanderthals, Homo sapiens's possible role in their downfall and how it become the last human species on Earth. Around 55,000 years ago, Homo sapiens ventured into Europe — only to find it was already occupied by Neanderthals who had lived there for almost 400,000 years. Ella Al-Shamahi, finds out just how close the two species became when she sees evidence of interbreeding. She reveals how during the Ice Age in Europe, Neanderthals held the evolutionary upper hand with a physiology better built for the cold. Yet against the odds, by around 30,000 years ago, Homo sapiens were the only species left. As she explores the demise of Neanderthals, Ella visits the ‘tunnel of bones’ in El Sidron cave, Spain where archaeologists have found the remains of 13 Neanderthal family members who were murdered and cannibalised.