The drama of geology is all around you. Have you ever been to Yellowstone National Park? If so, you have stood on a catastrophe in the making. The central region of the park is inside a collapsed volcanic crater that pulses with the hidden energy of magma deep below that will eventually explode in an eruption surpassing any in recorded history. Or have you ever driven in the rolling hills of the Piedmont region that extends from New Jersey to Alabama? Then you have crossed the core of an ancient mountain range that once rivaled the Himalayas. Now almost completely eroded away, these peaks were created 300 million years ago in the collision of tectonic plates that formed the supercontinent of Pangaea. Or have you ever noticed something as simple as tipped fence posts or leaning retaining walls? If so, then you have witnessed one of the most powerful and irresistible agents of geologic change, the ubiquitous force of gradual erosion called mass wasting.