Three years after landing his breakout role in the 1967 romantic comedy The Graduate, Dustin Hoffman was living in a townhouse in Manhattan’s Greenwich Village with his wife, Anne Byrne, and their daughter, Karina. Unbeknownst to them, the house next door was occupied by members of the leftist militant group the Weather Underground (a.k.a the Weathermen). But the young radicals weren’t just in town to hang out; they were using the subbasement at 18 West 11th Street to make bombs, one of which was meant to blow up the library at Columbia University.

On March 6, 1970, one of the Weathermen accidentally detonated some dynamite, causing the entire townhouse to explode. Three members of the group—Theodore Gold, Diana Oughton, and Terry Robbins—died as a result. Two others somehow managed to escape and remained on the run for over a decade. They were both apprehended later on, but refused to speak about the explosion.

“If everything is going to be alright, why are you shaking so hard?”

As for the Hoffmans, their home was severely damaged from the incident, but thankfully, they weren’t inside at the time. Their living room wall was left with a huge hole in it, and Hoffman’s desk had fallen into a crater next door that was caused by the blast. Hoffman was photographed that day retrieving valuables from the wreckage, including a large painting. New York Times critic Mel Gussow, who lived above Hoffman, remembered Hoffman telling his young daughter that everything would be alright, to which she replied, “If everything is going to be alright, why are you shaking so hard?”

Hoffman’s wife even found a map of the Columbia University tunneling system in the debris, something that was especially chilling to her because her father was the head librarian at Columbia. Hoffman later called it a life-changing and philosophy-changing experience. “It remains an abstraction until it happens to you,” he explained. “Since then, we’ve seen killings of abortion doctors, killings by Christian fundamentalists. At a certain point, the radical left and the radical right merged. They shook hands.”