Earthquakes are usually pretty scary, but they are a natural part of life on Earth. The reason they are devastating to humans is because we have built buildings and cities on top of ground that is often not as stable as we'd like it to be. And here's an important perspective: "Earthquakes don’t kill people, buildings do," says Bill Nye, as he explains what causes this geological phenomenon. Beneath the oceans' water, our planet has big slabs of land called tectonic plates that sit atop the earth's lava (a layer of molten rock that scientist call magma). There are gaps between these tectonic plates, so they slide and move over the magma and at times collide, causing a natural earthquake. But there are also manmade earthquakes, like the ones in the American Midwest. Bill Nye explains what's going on with these quakes, the basics of what to do if you're ever in an earthquake, and how science and smarter architecture can help humans survive the clashing of these tectonic plates beneath us. Bill Nye is the author of Unstoppable: Harnessing Science to Change the World.