1980
May 18 -- Mt. St. Helens in Washington erupts, killing 57 people and depositing ash in 11 states.

Nov. 4 -- The Reagan Revolution begins when Ronald Reagan is elected as the 40th president.

1981
Jan. 20 -- Twenty minutes after President Reagan takes the oath of office, Iran frees the 52 remaining hostages after 444 days of being held in the U.S. Embassy in Tehran.

Sept. 25 -- Arizona jurist Sandra Day O'Connor becomes the first woman to sit on the U.S. Supreme Court and would remain the only woman on the bench until Ruth Bader Ginsburg's confirmation in 1993.

1982
July 27 -- The Centers for Disease Control and Prevention gives a name to the disease it discovered 13 months earlier: Acquired Immuno-Deficiency Syndrome, or AIDS.

1983
Oct. 23 -- A truck bomb explodes at the U.S. Marine barracks in Beirut, Lebanon, killing 241 U.S. servicemen.

1984
Nov. 6 -- President Reagan is victorious in 49 states, easily winning re-election.

1985
May -- Three scientists publish in the science journal Nature their discovery of massive ozone layer depletion (the ozone hole) over the South Pole.

1986
Jan. 28 -- The space shuttle Challenger explodes, killing all seven aboard, including teacher Christa McAuliffe.

1987
Oct. 19 -- Day traders suffer through "Black Monday" when the Dow Jones Industrial Average falls 22.6 percent, setting off a worldwide economic crisis.

1988
Nov. 8 -- George H.W. Bush is elected president over Michael Dukakis by nearly 7 million votes, capturing 40 states in the Electoral College.

1989
Nov. 9 -- East Germany's Communist leaders allow open travel for its citizens, effectively clearing the way for the destruction of the Berlin Wall.

March 24 -- Traveling through the Prince William Sound, the Exxon Valdez oil tanker hits a reef and spills millions of gallons of crude oil along the Alaska coastline.

June 3-4 -- The Chinese army suppresses a pro-democracy protest in Tiananmen Square, Beijing, killing between 800 and 2,000 civilians.

1990
Feb. 2 -- Activist leader Nelson Mandela is freed from prison in South Africa. He preaches peace and reconciliation with the country's white population while pleading for the end of apartheid.

1991
Jan. 17 -- The United States launches Operation Desert Storm in the Persian Gulf.

Oct. 15 -- After his contentious confirmation hearing that famously involved sexual harassment charges, Clarence Thomas is confirmed by the U.S. Senate as an associate justice on the U.S. Supreme Court.

Dec. 31 -- The Union of Soviet Socialist Republics, or USSR, officially dissolves, bringing an end to the Cold War.

1992
April 30 -- Cops accused of beating Rodney King are acquitted of charges, spurring race riots across Los Angeles.

Aug. 24-28 -- Hurricane Andrew, a Category 5 storm, pummels the east coast of Florida.

Nov. 3 -- Bill Clinton is elected president and is the first of the baby boomer generation to take the office.

1993
Feb. 26 -- Islamist terrorists with ties to al-Qaida plant a car bomb in the parking garage of Tower One at the World Trade Center, killing six and injuring over 1,000 people.

April 19 -- A standoff between government authorities and members of the religious group the Branch Davidians, ends when FBI agents storm the Waco, Texas compound, killing 76 people inside.

Nov. 19 -- President Clinton brings Israeli Prime Minister Yitzhak Rabin and PLO figurehead Yasser Arafat together at the White House to sign the Oslo Accords.

1994
April 6 -- A plane carrying the presidents of Rwanda and Burundi is shot down near Kigali, Rwanda, killing the two leaders. Hutu militias begin rounding up Tutsis and massacring them in what is now known as the Rwandan genocide.

Nov. 8 -- Republicans, united behind the platform of a "Contract with America," take control of both houses in Congress for the first time in 40 years.

1995
April 19 -- Timothy McVeigh, with the help of accomplice Terry Nichols, leaves a Ryder van filled with 5,000 pounds of explosive material in front of the Alfred P. Murrah Federal Building in Oklahoma City. The explosion kills 168 people, including 19 children.

Oct. 3 -- Sports star O.J. Simpson is found not guilty on the charges that he murdered his wife, Nicole Brown Simpson, and her friend Ronald Goldman.

1996
July 27 -- The Centennial Park bombing kills one at the Summer Olympic Games in Atlanta.

1997
Feb. 22 -- In Nature magazine, scientists announce they have successfully cloned a sheep named Dolly.

Aug. 31 -- Britain's Princess Diana and boyfriend Dodi Fayed die in a car crash in a Paris tunnel. Investigators later conclude that the cause of the accident was that their driver was intoxicated and was attempting to avoid paparazzi.

1998
Jan. 21 -- Reports that President Clinton lied under oath about an affair with an intern named Monica Lewinsky culminate in his impeachment by the House of Representatives.

Aug. 7 -- Al-Qaida terrorists attack the U.S. Embassies in Tanzania and Kenya, killing more than 220 people, and bringing the name Osama bin Laden to the attention of many Americans.

1999
March 24 -- NATO commences a bombing campaign in Kosovo and Yugoslavia to stop Serbian President Slobodan Milosevic's violent ethnic cleansing operation in the Balkans.

April 20 -- Two students, Eric Harris and Dylan Klebold, open fire at Columbine High School in Littleton, Colo., killing 12 students and one teacher before committing suicide.

2000
Oct. 12 -- The USS Cole is attacked by suicide bombers while docked in Aden, Yemen, killing 17 U.S. soldiers.

Dec. 12 -- The U.S. Supreme Court votes 5-4 in favor of ending a contested recount, paving the way for George W. Bush to become the 43rd president.

2001
Sept. 11 -- Terrorists hijack commercial airliners and fly them into two World Trade Center towers in New York City, the Pentagon in Arlington, Va., and a field in Shanksville, Pa., killing nearly 3,000 people.

2002
Jan. 10 -- The Justice Department opens an investigation into the collapse of energy trading firm Enron Corp.

Oct. 2 -- Congress authorizes the use of military force in Iraq after leader Saddam Hussein refuses to let international inspectors into his nuclear facilities.

2003
March 20 -- A U.S.-led coalition of forces invades Iraq in March, removes Saddam from power, and President Bush announces the end of major combat in May.

2004
Nov. 2 -- President Bush wins re-election against Massachusetts Democratic Sen. John Kerry by 3 million votes.

2005
April 2 -- Pope John Paul II dies in April. Cardinal Joseph Ratzinger is elected as the new pope and takes the name Pope Benedict XVI.

Aug. 30 -- Hurricane Katrina hits the U.S. Gulf Coast, destroying many coastal cities. Subsequent flooding, caused by the levees in New Orleans breaking, strands thousands of residents who failed to evacuate earlier.