Kate Humble and Professor Iain Stewart present a four-day journey studying Earth's volcanoes. This first episode is broadcast from the world's most active volcano, Kilauea in the Hawaiian Islands.
Continuing their study of Kilauea, Kate and Iain broadcast from the site of the 1969 Mauna Ulu eruption. There's also reports from the Icelandic island of Heimeay, and Mount Puyehue in Chile.
In the last of the four programmes, comedian Ed Byrne does an experiment to mimic an eruption, while Kate and Iain look to the future of volcanic activity on the planet.
