On January 15, 1919, in Boston's North End, a 50-foot-tall tank holding 2.3 million gallons of molasses burst, unleashing a deadly wave that rose nearly 25 feet high at one point. The destructive flood threw people and horses about, smashed buildings, and even damaged the steel supports of an elevated railway. Rescuers had to wade through knee-deep molasses and sticky debris to reach survivors. Twenty-one people died in the disaster, another 150 were injured, and the cleanup lasted for weeks. The cause of the failure was determined to be faulty construction and poor maintenance.

1. This aerial view shows the site of the molasses storage tank explosion in the section of Commercial St. between Copps Hill and the playground of North End Park in Boston, Massachusetts, on January 15, 1919. The explosion of the steel vat, ninety feet in diameter and fifty-two feet in height, caused 2.3 million gallons of molasses to flood the area, killing 21 people and injuring 150. In the background is the Navy Yard in Charlestown.
AP
2. Firefighters and others stand in a pool of molasses after the explosion of a molasses storage tank owned by the United States Industrial Alcohol Company in Boston on January 15, 1919. About 2.3 million gallons of molasses flooded the area, killing 21 people, injuring 150, trapping a dozen horses, and destroying buildings, homes and part of the elevated train.
Courtesy trustees of the Boston Public Library/Leslie Jones Collection
3. Firemen standing in thick molasses after the disaster. Muck drips off the ladder's rungs.
Courtesy trustees of the Boston Public Library/Leslie Jones Collection
4. Section of tank after Molasses Disaster explosion at 1 p.m. on January 15, 1919
Courtesy trustees of the Boston Public Library/Leslie Jones Collection
5. Fire House no. 31, damaged in the Molasses Disaster
Courtesy trustees of the Boston Public Library/Leslie Jones Collection
6. Some of the wreckage caused by the explosion of the molasses storage tank in Boston on January 15, 1919, including damage to the steel support of the elevated train bridge
AP