Around noon on January 15, 1919, a group of firefighters was playing cards in Boston’s North End when they heard a tremendous crash. It was like roaring surf, one of them said later. Like a runaway two-horse team smashing through a fence, said another. A third firefighter jumped up from his chair to look out a window-“Oh my God!” he shouted to the other men, “Run!”

A 50-foot-tall steel tank filled with 2.3 million gallons of molasses had just collapsed on Boston’s waterfront, disgorging its contents as a 15-foot-high wave of molasses that at its outset traveled at 35 miles an hour. It demolished wooden homes, even the brick fire station. The number of dead wasn’t known for days. It would be years before a landmark court battle determined who was responsible for the disaster.

Stephen Puleo is author of the Boston Globe best seller The Boston Italians and the critically acclaimed Dark Tide: The Great Boston Molasses Flood of 1919. A former award-winning newspaper reporter and contributor to American History magazine, he holds a master’s degree in history and wrote his thesis on Italian immigration and the settlement of Boston’s North End. He donates a portion of his book proceeds to the Juvenile Diabetes Research Foundation (JDRF), the leading charitable funder and advocate of juvenile (Type 1) diabetes research.