The first Occupy Wall Street protest was held in the United States, as some 1,000 demonstrators marched in Manhattan before occupying Zuccotti Park; the movement, which eventually went global, sought to highlight corporate greed and income inequality, among other issues.

The New York Stock Exchange reopened after the September 11 attacks. It had been closed for four trading sessions, the longest closure since the Great Depression.

North Korea and South Korea were admitted to the United Nations. [Sort fact from fiction in our quiz about world organizations.]

Guns N’ Roses released (at midnight) the double album Use Your Illusion I and II, one of the most anticipated album releases in rock history. Even though some major retailers refused to sell the album because of its profanity, about 500,000 copies were purchased in the first two hours. [Find out why Slash joined Guns N’ Roses instead of Poison.]

Former Nicaraguan dictator Anastasio Somoza Debayle, who had fled Nicaragua after being overthrown by the Sandinistas, was assassinated in Paraguay; he had assisted the United States in the Bay of Pigs invasion of Cuba in 1961.

The American TV series M*A*S*H, based on the Robert Altman film (1970), debuted on CBS. It became hugely popular with both critics and viewers. [Find out how M*A*S*H fits into the history of television during the 1970s and ’80s.]

Folke Bernadotte was assassinated by members of a Zionist extremist organization while serving the United Nations as a mediator in the Israeli-Palestinian conflict.

During World War II the Soviet army invaded Poland from the east—joining Nazi Germany, which had launched its attack several weeks earlier—and the Polish government fled to Romania. [How much do you know about World War II?]

Sir Francis Chichester, who sailed around the world alone in 1966–67 in the yacht Gipsy Moth IV, was born. [Sort fact from fiction in our quiz about notable Englishmen.]

Union forces halted the Confederate advance on Maryland during the Battle of Antietam. The battle resulted in more than 26,000 casualties, making it one of the bloodiest days of the American Civil War. [Who won which battles during the American Civil War?]

The forces of Buenos Aires province, commanded by Governor Bartolomé Mitre, defeated those of the Argentine Confederation, led by Justo José de Urquiza, at the Battle of Pavón.

Harriet Tubman escaped from the Southern plantation where she was enslaved and later led other enslaved people to freedom in the North along the route of the Underground Railroad. [Test your knowledge of the history of slavery in North America.]

The U.S. Constitution was signed by 39 delegates of the Constitutional Convention. [Take our quiz about the history of the U.S. Constitution.]

The United States and the Lenape Nation signed the Treaty of Fort Pitt, the first written treaty between the U.S. and a Native tribe. In exchange for aid from the Lenape against the British during the American Revolution, the U.S. agreed to build a fort for their protection, encourage trade, and grant them representation in Congress as a 14th state. However, the treaty collapsed after the Americans did not, beyond the fort, fulfill their pledges.

Dutch microscopist Antonie van Leeuwenhoek published the first known representation of bacteria, which he called “animalcules.” The drawings were based on microorganisms he observed in plaque from his teeth using his microscopes.

The Swedish-Saxon army under King Gustav II Adolf of Sweden destroyed the army of the Roman Catholic Habsburg emperor Ferdinand II and the Catholic League, under Johann Tserclaes, Graf (count) von Tilly, in the Battle of Breitenfeld. [Take our quiz about the history of warfare.]

Pope Paul III suspended the Council of Trent after Charles V forbade the Spanish and German prelates to go to Bologna. [Test your knowledge of popes.]

The Polish nobility and their king, Louis I, signed the Pact of Koszyce, in which the nobles promised to accept the King’s choice of successor in exchange for a charter that guaranteed their basic rights and privileges. [How much do you know about European history?]