Overview: Millions of people live in the shadow of active volcanoes never knowing when their volatile neighbors could blow. In fact, predicting when a volcano will erupt is nearly impossible. But scientists around the world are getting closer to unlocking their deadly secrets. In this episode of Curiosity, you'll join the world's leading experts as they use state-of-the-art CGI compositing techniques to journey into the heart of these frightening powerhouses to demonstrate how they work and why they are so difficult to understand.