02:49
World in Motion: Earth's Tectonic Past and Future
Scientists attempt to reconstruct Earth's history so as to better understand the current state of geologic affairs, including those forces that cause plate movement.
01:54
World in Motion: Understanding Earth's Interior
Many scientists believe the plate tectonics process begins deep within the Earth. The challenge is to gather reliable data about an area that no one has ever actually explored--at least not directly.