A severe earthquake, centered in the vacation area of West Yellowstone, Montana, shook the ground and its inhabitants and visitors on August 17, 1959, at 11.37 pm. A mountainside fell, a lake formed, roads and houses disappeared, people were trapped, people died. The author of this narrative went to the area the day after the quake, took first-hand stories of the catastrophe, researched in the following months, and wrote this account within a year of the shaking. The printed source has many informative photographs. - Summary by David Wales