What's powerful enough to build a mountain — or blow the peak off one? A volcano! Join us on a virtual field trip deep below the earth's surface where volcanoes form. Then visit some of the world's most spectacular volcanoes.

Start your tour at the U.S. Geological Survey's site, where you'll find basic facts about volcanoes, like how they form and what causes them to erupt, and other resources for educators. Then for a more in-depth introduction, click through Volcano World's interactive The Earth's Layers and other Earth Science lessons. As you explore these sites, be sure to keep the U.S. Gological Survey's Glossary of Selected Volcano Terminology close by.

Once you've learned about how volcanoes grow and erupt, why not visit a few? Make your first stop the Cascade Range Volcanoes, where an interactive photo map will direct you to the most breathtaking (and powerful!) volcanoes in the United States. If you're feeling brave, explore the Weekly Volcanic Activity Report and find out what volcanoes are active right now. And since this is a virtual field trip, we're certainly not bound to earth — check out volcanoes on Mars and Venus in Extra-terrestrial Volcanoes.

With so many different volcanoes, it's easy to feel overwhelmed. If you have a question, check out the online Volcano FAQs. You'll find information on everything from the relationship between earthquakes and volcanoes, to how volcanoes effect the climate. 

So have you become an volcano expert yet? Head back over to the Volcano Games on Volcano World to play the Volcano Matching game, use the Volcano Simulator, solve the Volcano Crossword Puzzle, and more.