On May 31, 1889, the South Fork Dam failed, releasing more than 4.8 billion gallons of water, enough to fill roughly 7,300 Olympic-size swimming pools. The flood devastated Johnstown, Pennsylvania, and claimed the lives of over 2,200 people. Johnstown Flood National Memorial preserves the remains of the dam and tells the story of one of the deadliest disasters in American history. The site invites visitors to reflect on the tragedy and the remarkable relief efforts that followed.