— March 1, 1971: The Senate wing of the U.S. Capitol Building in Washington, D.C., is bombed by the radical left group Weather Underground. No one is killed.
— March 6, 1970: Three members of the Weather Underground accidentally blow themselves up in their townhouse in New York City's Greenwich Village while making bombs.
— Sept. 16, 1963: Four black girls are killed in a bombing at Birmingham, Ala.'s Sixteenth Street Baptist Church. Years later, juries convicted three Ku Klux Klansmen and one suspected accomplice died without ever having been charged. One of the four is still in prison and the others are dead.
— 1951-56: George Metesky, a former Consolidated Edison employee with a grudge against the company, sets off a series of blasts at New York landmarks, including Grand Central station and Radio City Music Hall. No one is killed. Known as The Mad Bomber, Metesky spends 16 years in a mental hospital.
— May 18, 1927: 45 people — 38 of them children — are killed when a school district treasurer, Andrew Kehoe, lines the Bath Consolidated School near Lansing, Mich., with hundreds of pounds of dynamite, and blows it up. Investigators say Kehoe, who also died in the blast, thought he would lose his farm because he couldn't pay property taxes used to build the school.
— Sept. 16, 1920: A bomb explodes in New York City's Wall Street area, killing 40 and injuring hundreds. Authorities conclude it was the work of "anarchists" and come up with a list of suspects, but all flee to Russia.
— Oct. 1, 1910: The Los Angeles Times building is dynamited during a labor dispute, killing 20 people. Two leaders of the ironworkers union plead guilty.
— May 4, 1886: A bomb blast during a labor rally at Chicago's Haymarket Square kills 11 people, including seven police officers, and injures more than 100. Eight "anarchists" are tried for inciting riot. Four are hanged, one commits suicide and three win pardons after seven years in prison.