Dr. Helen Czerski examines two of the hottest natural phenomena on Earth: lightning and volcanoes. More than 3 million lightning bolts strike the planet each day, each 5 times hotter than the surface of the sun and carrying millions of volts of electricity. It kills many thousands of people each year and many more are severely injured. Exactly how lightning works is only just being uncovered. Super-slow motion cameras, filming at several thousand frames per second, show its stunning and delicate path and reveal a rare form of upward lightning, triggered by our urban landscapes. Eyewitness footage show planes being struck by lightning, while a scientific expedition travels high into the atmosphere above a thunderstorm to catch on camera vast electrical discharges called sprites. Volcanoes are one of the most volatile, dangerous and dynamic forces on the planet. Now, user-generated footage is revealing rarely seen volcanic phenomena that challenge our understanding of these powerful forces. From Nyiragongo in the Democratic Republic of Congo, terrifying footage shows scientists risking their lives to uncover the secrets of the world's most dangerous volcano. In the lab, experiments reveal how this lava is a window into the planet's earliest origins. Infra-red footage of volcanic bombs in Chile have enabled scientists to understand why the explosive eruptions of Puyehue Cordon-Caulle last so long. The result of this flood of new images is pushing the boundaries of what was previously understood—and with better understanding scientists are more able to make sense of these amazing but often destructive forces of nature.