There are more than 6,000 abandoned villages in Italy - and that number is only set to increase. In this video, we are exploring the capital of them all: Craco, in the country's far south. Join us on a journey into the ruins, and one thousand years of his...

Why is a small region of China home to an extraordinary number of giant holes containing vast, little explored subterranean forests? One professor is on a dangerous mission to find out.