The unbelievable true story of one of the strangest disasters in history—part of the New York Times bestselling What Was? series, featuring 16 pages of photos.

On an unusually warm winter day in Boston, Massachusetts, a storage tank in the city's North End burst, flooding the neighborhood with 2.3 million gallons of molasses. The Red Cross, the Army, the Navy, and the Massachusetts Nautical School all launched courageous rescue missions to save people from the sticky and deadly mess, and it took hundreds of volunteers several weeks to clean up the streets. Ultimately, the disaster killed twenty-one people and injured 150 others. But the tragedy inspired reform that made our cities safer for all.