How do volcanoes erupt? What is lava and what happens when it cools? Where are the worldOs biggest volcanoes? Just stay cool--and let Volcano Vulcan, Dragon Explorer, take you around the hot-spots!How do volcanoes erupt? What is lava and what happens when it cools? Where are the worldOs biggest volcanoes? Just stay cool--and let Volcano Vulcan, Dragon Explorer, take you around the hot-spots!