Series showing how new camera technology is revealing the inner workings of the Earth's most spectacular natural wonders. Dr Helen Czerski examines the extraordinary new images - from eyewitnesses, scientists and film-makers - that are transforming our understanding of how and why these phenomena form. In this episode, Helen looks at volcanoes. With shocking eyewitness footage of eruptions, and new thermal imagery and ultra-high speed photography, we can now capture on camera the complex processes crucial to understanding how and why these forces of nature erupt.

• Helen Czerski