Water that lurks beneath the Earth's surface is usually far easier to ignore than the water that covers it—until that water bursts forth above ground as geysers and hot springs. This engaging volume explains to young readers where this water comes from and its relationship to volcanic activity underground. They will also learn where on Earth these spectacular eruptions are found, how geothermal energy can be harnessed for our use, and much more. Striking images of Old Faithful and other geysers fill the pages of this informative volume, while additional geological principles are imparted through boxed questions and terms.