The plot connected three radical organizations active in New York in the years before World War I. Charles Berg and Carl Hanson were members of the Lettish section of the Anarchist Red Cross, an organization with ties to the Russian Empire. Arthur Caron was affiliated with the Industrial Workers of the World. Together they had been collecting dynamite obtained from Russia and storing it at the apartment of Louise Berger, a fellow Anarchist Red Cross member who edited Emma Goldman's Mother Earth magazine. The group met at the Ferrer Center -- an anarchist school and gathering place on East 107th Street in East Harlem -- to plan their attack. The target was Rockefeller, whose violent suppression of labor disputes, particularly the recent Ludlow Massacre in Colorado, had made him a symbol of capitalist brutality in radical circles.

Louise Berger left her tenement at 1626 Lexington Avenue at nine o'clock that morning and walked to the Mother Earth offices on 119th Street. Fifteen minutes later, the dynamite detonated. The blast destroyed most of the top three floors and sent debris showering onto rooftops and streets for blocks. Berg, Hanson, and Caron were killed instantly. A fourth victim, Marie Chavez, had simply been renting a room in Berger's apartment and had no connection to the conspiracy. The explosion hurled Caron's body onto the fire escape. Chavez and Hanson were found inside the wreckage. Berg's body was torn apart by the force of the blast. Twenty others were injured, seven seriously enough to require hospitalization. The Ferrer Center stood only a few blocks away.

Alexander Berkman, one of America's most prominent anarchists, was implicated but never charged. According to later testimony from co-conspirator Charles Robert Plunkett, Berkman had attended at least two planning meetings at the Ferrer Center but chose to remain behind the scenes because he was on probation for his 1892 attempted assassination of steel magnate Henry Clay Frick. Plunkett also claimed that the bomb was never actually intended to destroy Rockefeller's home -- its detonation in Tarrytown would have been merely a "gesture of protest." Berkman denied any involvement or knowledge of the plan. His supporters believed him. His detractors did not. Berkman attended the funerals of Berg, Hanson, and Caron, which became rallies for the anarchist cause.

Marie Chavez was the only victim with no connection to the plot. She was simply living in the wrong apartment at the wrong time -- an innocent renter in a building where radical politics and high explosives occupied the floor above. Her death has no monument, no memorial. The explosion at 1626 Lexington Avenue belonged to a larger pattern of anarchist violence that convulsed American cities in the early twentieth century: the Wall Street bombing of 1920, the Palmer Raids of 1919, the Milwaukee Police Department bombing. But Lexington Avenue was different in one respect -- the conspirators killed themselves before they could kill their target. The bomb meant for one of the richest men in America instead destroyed a tenement in one of the poorest neighborhoods, taking the lives of the people who lived there alongside those who had built it.