Determined to challenge the growing American military presence in their territory, Native Americans in northern Wyoming lure Lieutenant Colonel William Fetterman and his soldiers into a deadly ambush on December 21, 1866. With 81 fatalities, the Fetterman Massacre was the army’s worst defeat in the West until the Battle of Little Bighorn in 1876.

General George S. Patton, commander of the U.S. 3rd Army, dies from injuries suffered not in battle but in a freak car accident. He was 60 years old.

Three months after a new French constitution was approved, Charles de Gaulle is elected the first president of the Fifth Republic by a sweeping majority of French voters. The previous June, France’s World War II hero was called out of retirement to lead the country when a military and civilian revolt in Algeria threatened France’s stability.

The film The Graduate opens at two theaters in New York: the Coronet on Third Avenue and the Lincoln Art Theater on Broadway. The film, based on a 1963 novel by Charles Webb, had a simple premise: As its screenwriter explained it, “this kid graduates college, has an affair with his parents’ best friend and then falls in love with the friend’s daughter.” (It was, he added, “the best pitch I ever heard.”) In other words, The Graduate was an uneasy exploration of what it meant to be young and adrift at a time of extraordinary confusion and upheaval. Anne Bancroft and Dustin Hoffman starred.

On December 21, 1970, rock star Elvis Presley is greeted at the White House by President Richard M. Nixon. Presley’s visit was not just a social call: He wanted to meet Nixon in order to offer his services in the government’s war on drugs.

On December 21, 1996, Margret Rey, who with her husband Hans created the popular Curious George children’s books about a mischievous monkey, dies at age 90 in Cambridge, Massachusetts. The Reys, both German Jews, escaped wartime Europe in 1940 and fled to America. The following year, the first Curious George book was published in the United States.

On December 21, 2012, the music video for "Gangnam Style," a song by the Korean rapper Psy, becomes the first YouTube video to garner one billion views. The video's global popularity is a case study in the power and unpredictability of viral internet content.