X-raying the Earth reveals a vast fault 80 miles off the Pacific Northwest coast. For more than 300 years, pressure has been silently building. When it slips, it will generate a megaquake and a tsunami that will devastate the region, threatening the lives of 15 million residents. Now scientists are racing to understand how bad the destruction will be when the “big one” hits.

X-Raying the Earth reveals that the Atlantic island of La Palma has collapsed several times in mega-landslides. Another collapse could trigger a tsunami with enough power to cross the Atlantic Ocean and decimate the U.S. East Coast. Now scientists race to understand what could trigger the tsunami — and just how devastating the catastrophe could be.

X-Raying the Earth shows that the largest volcano on the planet lies beneath Yellowstone National Park. It has erupted many times before — on a scale so big it has plunged the earth into a volcanic winter. No one alive has ever witnessed such a catastrophic event. Now the race is on to find out what could trigger a future eruption and how much warning we would get.