October 20:
1803 : U.S. Senate ratifies the Louisiana Purchase
On this day in 1803, the U.S. Senate approves a treaty with France providing for the purchase of the territory of Louisiana, which would double the size of the United States.
1947 : The Red Scare comes to Hollywood
The House Un-American Activities Committee (HUAC) of the U.S. Congress opens its investigation into communist infiltration of the American movie industry on October 20, 1947. Chaired by Congressman Parnell Thomas, the subsequent hearings focused on identifying political subversives among Hollywood actors and actresses, writers, and directors.
October 21:
1797 : USS Constitution launched
The USS Constitution, a 44-gun U.S. Navy frigate built to fight Barbary pirates off the coast of Tripoli, is launched in Boston Harbor. The vessel performed commendably during the Barbary conflicts, and in 1805 a peace treaty with Tripoli was signed on the Constitution's deck.
1966 : Mudslide buries school in Wales
On this day in 1966, an avalanche of mud and rocks buries a school in Aberfan, Wales, killing 148 people, mostly young students. The elementary school was located below a hill where a mining operation dumped its waste.
October 22:
1962 : Kennedy announces blockade of Cuba during the Missile Crisis
In a dramatic televised address to the American public, President John F. Kennedy announces that the Soviet Union has placed nuclear weapons in Cuba and, in response, the United States will establish a blockade around the island to prevent any other offensive weapons from entering Castro's state. Kennedy also warned the Soviets that any nuclear attack from Cuba would be construed as an act of war, and that the United States would retaliate in kind.
1966 : Supremes hit No. 1
The Supremes become the first all-female group to score a No. 1 album, with Supremes a Go-Go.
October 23:
1971 : Disney World opens
Walt Disney World opens in Orlando, Florida, 16 years after Disneyland opened in Anaheim, California. Disney World, featuring rides and characters from Disney's beloved movies, would later include EPCOT Center (which opened in 1982), based on Walt Disney's vision of a Utopian planned community. (EPCOT stands for Experimental Prototype Community of Tomorrow.) The Walt Disney Company launched a real planned community, Celebration, Florida, in 1996.
1921 : Unknown Soldier is selected 
On October 23, 1921, in the French town of Chalons-sur-Marne, an American officer selects the body of the first "Unknown Soldier" to be honored among the approximately 77,000 United States servicemen killed on the Western Front during World War I.
October 24: 
1901 : First barrel ride down Niagara Falls
Daredevil Annie Edson Taylor initiates a famous stunt tradition when she goes over Niagara Falls in a wooden barrel. Taylor, who performed the feat on her birthday, went over the 175-foot-tall Horseshoe Falls on the Canadian side of Niagara inside a barrel five feet high and three feet in diameter. A leather harness and cushions lined the barrel to protect Taylor during her fall, and she emerged shaken but unhurt in the river below.
1945 : The United Nations is born
On this day in 1945, the United Nations Charter, which was adopted and signed on June 26, 1945, is now effective and ready to be enforced.
October 25:
1944 : First kamikaze attack of the war begins
On this day in 1944, during the Battle of the Leyte Gulf, the Japanese deploy kamikaze ("divine wind") suicide bombers against American warships for the first time. It will prove costly--to both sides.
1764 : John Adams marries Abigail Smith
On this day in 1764, future President John Adams marries Abigail Smith. This devoted couples prolific correspondence during their married life has provided entertainment and a glimpse of early American life for generations of history buffs.
October 26:
2001 : George W. Bush signs the Patriot Act 
On this day in 2001, President George W. Bush signs the Patriot Act, an anti-terrorism law drawn up in response to the attacks on the Pentagon and World Trade Center on September 11, 2001.
1825: The Erie Canal Opens connecting the Great Lakes and the Atlantic Ocean via the Hudson River.
