Prior to their extinction, Neanderthals had been widespread in Europe for 100,000 years. Then 50,000 years ago, modern humans moved into Europe from Africa. Twenty-six thousand years after that the last Neanderthal died. At one time it was thought that the Neanderthals were killed by climate change, but this theory has now been discounted. So why did the Neanderthals perish? Probably they were killed by the humans.