The United States declared war on Britain, beginning the War of 1812.

Juneteenth: General Gordon Granger proclaimed the freedom of all slaves in Texas, the last state of the Confederacy to have emancipation enforced.

The United States and Soviet Union agreed to establish a 'hotline' communication system to prevent nuclear confrontations.

Three civil rights workers disappeared in Mississippi, starting a summer of violence during the Civil Rights Movement.

The Servicemen’s Readjustment Act (G.I. Bill) was signed into law, providing benefits to millions of World War II veterans.

Title IX of the Education Amendments was signed into law, prohibiting sex-based discrimination in federally funded education programs.

Start of the Berlin Airlift, one of the first major international crises of the Cold War.

The Battle of Little Bighorn, also known as Custer's Last Stand, occurred in Montana.

The United Nations Charter was signed in San Francisco, marking the establishment of the United Nations.

President Harry S. Truman ordered U.S. armed forces to assist South Korea in repelling the invasion by North Korea, marking the start of the Korean War.

The Treaty of Versailles was signed, officially ending World War I.

President Dwight D. Eisenhower signed the Federal-Aid Highway Act, creating the Interstate Highway System.

The 26th Amendment to the United States Constitution was ratified, lowering the voting age from 21 to 18.

The Articles of Confederation were ratified, formally uniting the American colonies under a national government.

Congress passed the first Reconstruction Act, dividing the South into five military districts to ensure fairness in elections.

"The Star-Spangled Banner" was adopted as the national anthem of the United States.

The U.S. Constitution went into effect as the first Federal Congress met in New York City.

The Hula-Hoop, a toy that became a huge fad across America, was patented by Wham-O.

The Dred Scott decision was delivered by the U.S. Supreme Court, stating that slaves were not citizens and had no standing in court.

"Bloody Sunday" occurred during the Selma to Montgomery marches when civil rights demonstrators were brutally attacked by police.

The February Revolution began in Russia (Julian calendar date, March 8 Gregorian calendar), leading to the abdication of Tsar Nicholas II.

The ironclad ships USS Monitor and CSS Virginia fought in the Battle of Hampton Roads, revolutionizing naval warfare.

Alexander Graham Bell made the first successful telephone call by saying "Mr. Watson, come here, I want to see you."

A massive 9.0 magnitude earthquake and subsequent tsunami struck Japan, causing widespread destruction and triggering the Fukushima nuclear disaster.

President Franklin D. Roosevelt gave his first "fireside chat" radio address to the American people.

William Herschel discovered the planet Uranus, expanding the known boundaries of the solar system.

Jack Ruby was convicted of murdering Lee Harvey Oswald, the accused assassin of President John F. Kennedy.

President Woodrow Wilson began his second term, advocating for peace but leading the United States into World War I just a month later due to ongoing German aggressions and the Zimmermann Telegram.

The United States Military Academy at West Point was established.

New York City held its first St. Patrick's Day parade.

Cosmonaut Alexei Leonov performed the first spacewalk during the Voskhod 2 mission.

The United States, along with coalition forces, began the invasion of Iraq.

Harriet Beecher Stowe's "Uncle Tom's Cabin" was published, which played a significant role in stirring anti-slavery sentiments during the pre-Civil War era.

The Sharpeville Massacre occurred in South Africa when police opened fire on a crowd of peaceful black protesters, killing 69 people.

The British Parliament passed the Stamp Act, imposing a direct tax on the American colonies to raise revenue.

President Barack Obama signed the Affordable Care Act into law, marking a major overhaul of the U.S. healthcare system.

The Exxon Valdez oil spill occurred in Alaska, one of the most devastating human-caused environmental disasters.

The Triangle Shirtwaist Factory fire in New York City killed 146 workers, leading to significant improvements in factory safety standards.

The Egypt-Israel Peace Treaty was signed, ending 30 years of conflict between the two nations.

The Good Friday Earthquake, the most powerful in U.S. history, struck Southcentral Alaska, causing widespread damage.

The Three Mile Island nuclear power plant accident occurred in Pennsylvania, resulting in widespread fears about the safety of nuclear power.

The last U.S. troops withdrew from Vietnam, ending direct military involvement in the Vietnam War.

President Ronald Reagan was shot and wounded by John Hinckley Jr. during an assassination attempt in Washington, D.C.

The Eiffel Tower was officially opened to the public at the 1889 World's Fair in Paris.

The Empire State Building, the tallest building in the world at the time, was officially opened in New York City.

Osama bin Laden, the mastermind behind the September 11 attacks, was killed by U.S. Navy SEALs in Pakistan.

Washington, D.C. is incorporated as a city; it was originally established as the capital in 1790.

Kent State shootings: National Guardsmen fired on anti-war protesters at Kent State University in Ohio, killing four students.

Alan Shepard became the first American to travel into space, making a 15-minute suborbital flight.

The Hindenburg disaster occurred as the German zeppelin caught fire and was destroyed within a minute while attempting to dock in New Jersey.

The British ocean liner RMS Lusitania was sunk by a German U-boat, killing 1,198 including 128 Americans, influencing the U.S. decision to enter World War I.

Victory in Europe Day (VE Day) marked the formal acceptance by the Allies of World War II of Nazi Germany's unconditional surrender.

The U.S. Food and Drug Administration (FDA) approved the first commercially produced birth control pill in the world.

The Golden Spike was driven at Promontory, Utah, marking the completion of the first Transcontinental Railroad in the United States.

The Battle of Hamburger Hill during the Vietnam War began; it was one of the war's most controversial battles.

The Soviet Union lifted its blockade of Berlin, ending the Berlin Airlift which saw Western planes deliver food and supplies to West Berlin.

The United States declared war on Mexico, starting the Mexican-American War over disputes involving Texas.

Lewis and Clark departed from St. Louis, Missouri, on their expedition to explore the American Northwest.

During his presidential campaign, George Wallace was shot five times by Arthur Bremer in Laurel, Maryland.

The first Academy Awards ceremony was held in Hollywood, with the movie 'Wings' winning Best Picture.

Brown v. Board of Education: The U.S. Supreme Court declared state laws establishing separate public schools for black and white students unconstitutional.

Mount St. Helens erupted in Washington State, causing massive destruction and resulting in 57 deaths.

The U.S. Congress passed the Emergency Quota Act, establishing national quotas on immigration.

President Abraham Lincoln signed the Homestead Act into law, providing 160 acres of public land for free to settlers in the West.

Clara Barton founded the American Red Cross in Washington, D.C.

The Great Migration began along the Oregon Trail, with a wagon train of one thousand pioneers.

Bank robbers Bonnie and Clyde were ambushed and killed by police in Bienville Parish, Louisiana.

The Brooklyn Bridge, linking Manhattan and Brooklyn in New York City, was opened to the public.

The Constitutional Convention opened in Philadelphia with George Washington presiding.

President Andrew Johnson was acquitted in his impeachment trial by just one vote in the U.S. Senate.

The Federal Securities Act, designed to regulate the stock market, was signed into law by President Franklin D. Roosevelt.

President Andrew Jackson signed the Indian Removal Act, which authorized the forced relocation of Native American tribes living east of the Mississippi.

Wisconsin was admitted as the 30th state of the United States.

The Lincoln Memorial was dedicated in Washington, D.C.

The Johnstown Flood occurred after a dam burst, killing over 2,200 people in Pennsylvania.

The United States successfully detonated the first hydrogen bomb, codenamed "Ivy Mike," at Enewetak Atoll in the Pacific Ocean.

Howard Hughes piloted the H-4 Hercules, commonly known as the "Spruce Goose," on its first and only flight.

The United States presidential election took place, one of the most contentious in recent history.

Barack Obama was elected as the 44th President of the United States, becoming the first African American to hold the office.

Franklin D. Roosevelt was elected to an unprecedented third term as U.S. President.

Abraham Lincoln was elected as the 16th President of the United States, leading to the secession of Southern states.

Richard Nixon delivered his famous "You won't have Nixon to kick around anymore" speech after losing the California governor's race.

Donald Trump was elected as the 45th President of the United States in a surprising election outcome.

The Northeast blackout occurred, affecting over 30 million people in the United States and Canada.

The SS Edmund Fitzgerald sank in Lake Superior during a storm, claiming the lives of all 29 crew members.

World War I ended with the signing of the Armistice by Germany and the Allies in France.

Joseph Stalin became the undisputed ruler of the Soviet Union as Leon Trotsky was expelled from the Communist Party.

The Vietnam Veterans Memorial was dedicated in Washington, D.C.

Apollo 12, the sixth crewed flight in the United States Apollo program and the second to land on the Moon, was launched from Kennedy Space Center.

The Articles of Confederation were adopted by the Continental Congress.

Oklahoma was admitted as the 46th state of the United States.

Elizabeth I became Queen of England, marking the start of the Elizabethan era.

American and Canadian railroads instituted five standard continental time zones, ending the confusion of thousands of local times.

President Abraham Lincoln delivered the Gettysburg Address at the dedication ceremony for the military cemetery at Gettysburg, Pennsylvania.

The Nuremberg trials began, with 24 high-ranking Nazis tried for atrocities committed during World War II.

Millions of viewers tuned in to find out "Who shot J.R.?" on the TV show "Dallas," making it one of the most watched television episodes in history.

President John F. Kennedy was assassinated in Dallas, Texas.

The first issue of the pictorial magazine Life was published, featuring a cover photo of the Fort Peck Dam by Margaret Bourke-White.

D.B. Cooper parachuted from a Northwest Orient Airlines plane with $200,000 in ransom money, never to be seen again.

British troops evacuated New York City, their last military position in the United States during the Revolutionary War.