During the last Ice Age, millions of large animals roamed the Earth, from wooly mammoths and giant sloths to cave lions and saber-toothed cats. But as the temperatures rose, three-quarters of these species died out. What happened? Can environmental changes alone really explain this mass extinction, or did humans - who at this very time were beginning their conquest of the planet - play a key role? To find out, researchers around the world are hunting and studying fossils in their search for answers to solve the mystery of the Ice Age giants.

Scientists speculate why the end of the last Ice Age caused the extinction of some of Earth's largest animals.

Follow one mammoth expert as he traces the legendary giants from Africa to the Yukon.

Looking at whether the history of early human evolution should be rewritten. For decades, most experts have been convinced that Africa is the cradle of mankind and many fossil finds from Kenya, Ethiopia, South Africa and Chad seemed to prove it.

Unlike what people may think, Krakatoa was not the biggest volcanic eruption in history. More than two hundred years ago, on April 10th 1815, Mount Tambora in Eastern Indonesia became a merciless killer. It unleashed the most deadly volcanic eruption in human memory, wiping out at least 117,000 people. And an entire civilization and its language disappeared. But the killing didn’t stop there. It has now been proven that this eruption could have triggered an extraordinary and little known cataclysmic event: worldwide climate change.