It happened in a crowded section of Boston 99 years ago this week. 21 people were left dead and dozens badly injured. This disaster is now referred to as "The Great Molasses Flood of 1919."

According to history.com, a molasses holding tank burst and caused a wave of the scalding hot syrup to flood Commercial Street in the city's north end. The wall of heavy molasses was 15-feet high and crushed people. horses and some building that was in its path. Even part of a raised train platform was wiped out by the wave when it's supporting beams were melted.

The History Channel website says that the 50-foot high steel tank holding the hot molasses burst at about 12:40 in the afternoon. It was a mild winter day in Boston and hundreds of people were in the nearby streets for work and lunch hour shopping. The path of death and destruction covered half-a-mile. It took days to recover all the bodies of those killed.

According to reports, the smell of molasses lingered on the streets in the north end of Boston for weeks, and the water in Boston Harbor remained brown for several months.  The company that owned the ruptured tank eventually paid hundreds of thousands of dollars to victims and their family members.