Around lunchtime on January 15, 1919, a 50-foot-tall molasses tank ruptured and spilled out onto the streets of the North End.  According to History.com, more than 2 million gallons of thick liquid poured out like a tsunami wave, reaching speeds of up to 35 miles per hour. The molasses destroyed buildings, knocked an elevated train off of its tracks, trapped horses, and killed 21 people, with 150 more injuries.

According to Stephen Puleo, author of The Dark Tide: The Great Molasses Flood of 1919, the tank was built a few years before and was known to leak. Kids in the neighborhood would fill up pails of molasses, so it was no surprise that “a situation” could arise. Structural engineers determined that the tank’s walls were too thin to hold the heavy contents. A new shipment arrived, the walls burst, and the rest is history.

Image via the City of Boston Instagram