Great Molasses Flood of 1919

On January 15, 1919, a 2.3 million gallon tank of molasses exploded on the North End of Boston, Massachusetts causing the death of 21 people and the injury of 150 people, the reason it exploded was because of its poor construction, weather, and cracks, there is a myth that if you go to the North End of Boston you can still smell Molasses. 
=== Clean up ===
To clean up the molasses they used salt water from a fire boat to wash away the water, but there is supposedly still some molasses left.https://en.wikipedia.org/wiki/Great_Molasses_Flood