From The History Channel:

"""The South Fork Dam in Pennsylvania collapses on May 31, 1889, causing the Johnstown Flood, killing more than 2,200 people.

Johnstown is 60 miles east of Pittsburgh in a valley near the Allegheny, Little Conemaugh and Stony Creek Rivers. It is located on a floodplain that has been subject to frequent disasters. A dam was built in 1840 on the Little Conemaugh River, 14 miles upstream from Johnstown. Nine hundred feet by 72 feet, it was the largest earth dam (made of dirt and rock, rather than steel and concrete) in the United States and it created the largest man-made lake of the time, Lake Conemaugh. The dam was part of an extensive canal system that became obsolete as the railroads replaced the canal as a means of transporting goods. As the canal system fell into disuse, maintenance on the dam was neglected."""

The properties around the lake and dam were owned by some of the wealthiest people in the region. None would take the responsibility to do maintenance and repairs of the dam. They did nothing to see that lake wasn't over filled or additional water was diverted. When the dam broke most lost nothing more than a dock and boat. But the residents of Johnstown and those down river were those who suffered.

Don