The ground beneath your feet is solid, right? After all, how could we build houses and bridges if the land was moving all the time? Actually, the ground beneath us really is moving very slowly all the time In Fault Lines and Tectonic Plates: Discover What Happens When the Earth's Crust Moves, readers ages 9 through 12 learn what exactly is going on under the dirt. When slowly drifting continents bump up against each other along fault...