Apple Computer Company was formed by Steve Jobs, Steve Wozniak, and Ronald Wayne, marking the beginning of the company that would become a giant in the technology sector.

President Woodrow Wilson asked Congress for a declaration of war against Germany, leading the United States into World War I.

The Pony Express began its first run from St. Joseph, Missouri, to Sacramento, California, dramatically reducing the time it took for mail delivery across the United States.

Civil rights leader Martin Luther King Jr. was assassinated in Memphis, Tennessee, sparking riots and national mourning.

Julius and Ethel Rosenberg were sentenced to death for conspiracy to commit espionage, related to passing information about the atomic bomb to the Soviet Union.

The first modern Olympic Games opened in Athens, Greece, revitalizing the ancient competitions.

The World Health Organization (WHO) was established by the United Nations to coordinate international health efforts.

Hank Aaron of the Atlanta Braves hit his 715th career home run, breaking Babe Ruth's long-standing record.

Confederate General Robert E. Lee surrendered to Union General Ulysses S. Grant at Appomattox Court House in Virginia, effectively ending the American Civil War.

RMS Titanic set sail from Southampton, England on her maiden (and only) voyage, destined for disaster in the North Atlantic.

President Harry S. Truman relieved General Douglas MacArthur of his commands in Korea, sparking public controversy over civilian control of the military.

The Civil War began with Confederate forces firing on Fort Sumter in Charleston Harbor, South Carolina.

Thomas Jefferson, the third President of the United States and principal author of the Declaration of Independence, was born in Shadwell, Virginia.

The Titanic hit an iceberg at 11:40 PM in the North Atlantic, setting the stage for a tragic sinking that would occur in the early hours of April 15.

Jackie Robinson broke Major League Baseball's color barrier by playing his first game with the Brooklyn Dodgers.

The Virginia Tech shooting became the deadliest school shooting in U.S. history when a student killed 32 people before committing suicide.

The Bay of Pigs Invasion, a failed military invasion of Cuba undertaken by CIA-sponsored paramilitary group Brigade 2506, occurred.

A massive earthquake and subsequent fires devastated San Francisco, killing over 3,000 people and destroying much of the city.

The Alfred P. Murrah Federal Building in Oklahoma City was bombed, killing 168 people in the deadliest act of domestic terrorism in U.S. history.

The Deepwater Horizon oil rig exploded in the Gulf of Mexico, leading to one of the worst environmental disasters in U.S. history.

Texas forces won the Battle of San Jacinto, securing Texas' independence from Mexico.

The first Earth Day was celebrated in the United States, marking the beginning of the modern environmental movement.

William Shakespeare, English playwright and poet, was born in Stratford-upon-Avon, England (traditional date).

The Library of Congress was established in Washington, D.C., providing the United States with its oldest federal cultural institution.

Scientists James Watson and Francis Crick published a paper describing the double helix structure of DNA.

The Chernobyl nuclear disaster occurred, releasing radioactive material across Europe in one of the most severe nuclear power plant accidents in history.

South Africa held its first democratic elections after the end of apartheid, with Nelson Mandela elected as President.

The mutiny on the Bounty occurred, in which Lieutenant William Bligh and 18 sailors were set adrift by a rebellious crew led by Fletcher Christian.

The Los Angeles riots began after the acquittal of police officers videotaped beating Rodney King, resulting in widespread violence and looting.

George Washington was inaugurated as the first President of the United States in New York City.

MTV was launched, changing the music industry and popular culture with the broadcasting of its first music video, 'Video Killed the Radio Star.'

The signing of the United States Declaration of Independence took place. Although the declaration was adopted on July 4, the actual signing occurred almost a month later.

Christopher Columbus set sail from Spain on his voyage that would lead him to the Americas, significantly impacting global history.

The bodies of three civil rights workers were found in Mississippi, a case that drew national attention to the civil rights struggle.

The Battle of Mobile Bay occurred during the American Civil War, marked by Admiral David Farragut's famous order, 'Damn the torpedoes, full speed ahead!'

The United States dropped the atomic bomb on Hiroshima, Japan, leading to Japan's surrender and the end of World War II.

Congress passed the Gulf of Tonkin Resolution, giving President Lyndon B. Johnson broad war powers in Vietnam.

President Richard Nixon announced his resignation, effective the next day, due to the Watergate scandal.

The United States dropped a second atomic bomb on Nagasaki, Japan, three days after the bombing of Hiroshima.

The Smithsonian Institution was founded in Washington, D.C., after James Smithson, a British scientist, bequeathed his estate to the United States for the 'increase and diffusion of knowledge.'

The Mall of America, the largest shopping mall in the U.S. at the time, opened in Bloomington, Minnesota.

IBM released its first personal computer, the IBM PC, which had a profound impact on the computing industry.

Construction began on the Berlin Wall, which would stand as a divisive symbol of the Cold War until 1989.

President Franklin D. Roosevelt signed the Social Security Act into law, creating a safety net for the elderly and unemployed.

The Woodstock Music Festival opened in upstate New York, symbolizing the counterculture movement of the 1960s.

Elvis Presley, the king of rock 'n' roll, died at his Graceland home in Memphis, Tennessee.

The first commercial Compact Discs (CDs) were produced in Germany, heralding a new era for the music industry.

The 19th Amendment to the U.S. Constitution was ratified, granting American women the right to vote.

The USS Constitution defeated the British frigate HMS Guerriere off the coast of Nova Scotia during the War of 1812, earning the nickname 'Old Ironsides.'

President Andrew Johnson formally declared the Civil War over, even though the fighting had stopped months earlier.

Hawaii became the 50th state of the United States.

The Haitian Revolution began with a massive slave uprising in Saint-Domingue, which would lead to the establishment of Haiti as an independent nation.

Italian-born anarchists Nicola Sacco and Bartolomeo Vanzetti were executed, concluding a controversial murder trial and worldwide protests.

British troops burned the White House during the War of 1812.

The National Park Service was established by an act signed by President Woodrow Wilson.

The 19th Amendment, guaranteeing women the right to vote, took effect.

The eruption of Krakatoa began, one of the most violent volcanic events in recorded history.

Martin Luther King Jr. delivered his iconic 'I Have a Dream' speech during the March on Washington for Jobs and Freedom.

Hurricane Katrina, one of the deadliest and most costly hurricanes in U.S. history, struck the Gulf Coast.

Thurgood Marshall was confirmed as the first African American Justice of the U.S. Supreme Court.

Princess Diana died in a car crash in Paris, an event that had a profound impact on the United States and the world.

Rosa Parks was arrested for refusing to give up her seat on a bus in Montgomery, Alabama, sparking the Montgomery Bus Boycott.

The first successful nuclear chain reaction was initiated by Enrico Fermi in Chicago, part of the Manhattan Project.

The Bhopal chemical disaster occurred in India, one of the world's worst industrial catastrophes.

George Washington delivered his farewell address to his officers at Fraunces Tavern in New York City.

Prohibition ended in the United States with the ratification of the 21st Amendment, repealing the 18th Amendment.

The Washington Monument was completed and dedicated in Washington, D.C.

The attack on Pearl Harbor by Japan prompted the United States to enter World War II.

John Lennon, former member of The Beatles, was assassinated in New York City.

The first edition of "Walden" by Henry David Thoreau was published.

The first Nobel Prizes were awarded in Stockholm, Sweden, in the fields of Physics, Chemistry, Medicine, Literature, and Peace.

Germany and Italy declared war on the United States, bringing America into the European theater of World War II.

The U.S. Supreme Court reached a decision in Bush v. Gore, effectively resolving the 2000 presidential election in favor of George W. Bush.

Saddam Hussein, former Iraq President, was captured near his hometown of Tikrit during Operation Red Dawn.

Norwegian explorer Roald Amundsen became the first person to reach the South Pole.

The Bill of Rights, the first ten amendments to the United States Constitution, was ratified.

The Boston Tea Party took place as a protest against British taxes.

The Wright brothers made the first powered flight in Kitty Hawk, North Carolina.

Slavery was abolished in the United States with the ratification of the 13th Amendment.

President Bill Clinton was impeached by the House of Representatives.

The Louisiana Purchase was completed, nearly doubling the size of the United States.

The Pilgrims landed at Plymouth, Massachusetts, establishing the Plymouth Colony.

The Brandenburg Gate in Berlin reopened, symbolizing the reunification of East and West Germany.

George Washington resigned as commander-in-chief of the Continental Army at the Maryland State House.

The Treaty of Ghent was signed, ending the War of 1812 between the United States and Britain.

George Washington crossed the Delaware River, leading to a surprise attack against Hessian forces at Trenton, New Jersey.

The Soviet Union was officially dissolved, marking the end of the Cold War.

Charles Darwin embarked on his journey aboard the HMS Beagle, during which he would develop his theory of evolution.

Iowa was admitted as the 29th state of the United States.

The Wounded Knee Massacre occurred, one of the last major conflicts between the Plains Indians and U.S. forces.

The Union of Soviet Socialist Republics (USSR) was established.

The United States handed over control of the Panama Canal to Panama, fulfilling the terms of the 1977 Torrijos-Carter Treaties.

Four African American college students sat down at a segregated Woolworth's lunch counter in Greensboro, North Carolina, sparking a sit-in movement.

The Treaty of Guadalupe Hidalgo was signed, ending the Mexican-American War and ceding large territories from Mexico to the U.S.

The 15th Amendment was ratified, granting African American men the right to vote.

Facebook, a major social media platform, was founded by Mark Zuckerberg while he was a student at Harvard University.

The U.S. Congress passed the Immigration Act of 1917, which imposed literacy tests on immigrants and marked a shift towards restrictive immigration policies.

Massachusetts ratified the U.S. Constitution and became the sixth state to join the Union.

The Beatles arrived in America for the first time, ushering in the British Invasion of rock bands.

The Boy Scouts of America was incorporated by William D. Boyce.