On December 6, 1865, the 13th Amendment to the U.S. Constitution, officially ending the institution of slavery, is ratified. “Neither slavery nor involuntary servitude, except as a punishment for crime whereof the party shall have been duly convicted, shall exist within the United States, or any place subject to their jurisdiction.” With these words, the single greatest change wrought by the Civil War was officially noted in the Constitution.

At 9:05 a.m., in the harbor of Halifax in the Canadian province of Nova Scotia, the most devastating manmade explosion in the pre-atomic age occurs when the Mont Blanc, a French munitions ship, explodes 20 minutes after colliding with another vessel. More than 1,800 people died.

On December 6, 1933, a federal judge rules that Ulysses by James Joyce is not obscene. The book had been banned immediately in both the United States and England when it came out in 1922. Three years earlier, its serialization in an American review had been cut short by the U.S. Post Office for the same reason. Fortunately, one of Joyce’s supporters, Sylvia Beach, owner of the Paris-based bookstore Shakespeare and Co., published the novel herself in 1922.

President Roosevelt—convinced on the basis of intelligence reports that the Japanese fleet is headed for Thailand, not the United States—telegrams Emperor Hirohito with the request that “for the sake of humanity,” the emperor intervene “to prevent further death and destruction in the world.”

On December 6, 1969, in a shocking act of violence, a Hells Angel biker stabs to death an 18-year-old concertgoer a during a set by the British rock group Rolling Stones at the Altamont music festival.