The Wall Street bombing occurred at 12:01 pm on Thursday, September 16, 1920, in the Financial District of Manhattan, New York City. The blast killed thirty people immediately, and another ten died later of wounds sustained in the blast. There were 143 seriously injured, and the total number of injured was in the hundreds.: 160–61 The bombing was never solved, although investigators and historians believe it was carried out by Galleanists (Italian anarchists), a group responsible for a series of bombings the previous year. The attack was related to postwar social unrest, labor struggles, and anti-capitalist agitation in the United States.

The Wall Street bomb killed more people than the 1910 bombing of the Los Angeles Times, which was the deadliest act of terrorism on U.S. soil up to that point.