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 Sidrón cave, Spain where archaeologists have found the remains of 13 Neanderthal family members who were murdered and cannibalised.

Around 12,000 years ago, as the Ice Age finally thaws, humanity makes a dramatic shift - abandoning nomadic life for permanent settlements.

In Turkey, Ella Al-Shamahi visits the world's oldest temple, Gobekli Tepe, and one of the largest early towns, Catalhoyuk - a prototype in urban living, with no streets and honeycombs of dwellings accessed through the roofs. But living in densely populated towns, with livestock alongside them and dead ancestors buried beneath their houses, brought new challenges: disease and evidence of unrest and brutal violence.

In Egypt, Ella finds out how cities began to thrive rather than collapse. And in a turquoise mine in the Sinai desert, she discovers how migrant workers were responsible for creating the first alphabet.