New York Cityâ€™s deadliest terror attack before 9/11 took place at the corner of Wall Street and Broadway on September 16, 1920, when a horse-drawn wagon was abandoned by its driver.
A bomb consisting of one hundred pounds of dynamite packed with five hundred pounds of cast-iron slugs violently vomited red-hot shrapnel and destruction in every direction. A number of passers-by were instantly vaporized by the extreme heat and pressure. The blast sent a nearby automobile careening through the air as countless jagged iron fragments ripped through the crowd.
Damn Interesting, where you often find history youâ€™ve never heard, has the story. Warning: gory details. Link