The tallest volcano in Java, Indonesia, erupted over the weekend, killing at least 15 people. Many more are in the hospital and dozens are missing. The eruption caught local monitors off guard, and thousands were forced to flee with little warning. Halfway around the world, a volcano in La Palma, located in Spain’s Canary Islands, is still spewing lava and ash, after 11 weeks of activity. The World’s Marco Werman speaks to Cornell University volcano expert Esteban Gazel about what scientists are learning from La Palma and what it can teach the rest of the world.