Iconic images from the Associated Press

A Chinese man stands alone to block a line of tanks heading east on Beijing’s Cangan Blvd. in Tiananmen Square on June 5, 1989. The man, calling for an end to the recent violence and bloodshed against pro-democracy demonstrators, was pulled away by bystanders, and the tanks continued on their way. The Chinese government crushed a student-led demonstration for democratic reform and against government corruption, killing hundreds, or perhaps thousands of demonstrators in the strongest anti-government protest since the 1949 revolution. Ironically, the name Tiananmen means “Gate of Heavenly Peace”.

In this Oct. 2, 2008 file photo, Republican vice presidential candidate Alaska Gov. Sarah Palin winks as she speaks during her vice presidential debate against Democratic vice presidential candidate Sen. Joe Biden, D-Del., at Washington University in St. Louis, Mo.

South Vietnamese forces follow after terrified children, including 9-year-old Kim Phuc, center, as they run down Route 1 near Trang Bang after an aerial napalm attack on suspected Viet Cong hiding places, June 8, 1972. A South Vietnamese plane accidentally dropped its flaming napalm on South Vietnamese troops and civilians. The terrified girl had ripped off her burning clothes while fleeing. The children from left to right are: Phan Thanh Tam, younger brother of Kim Phuc, who lost an eye, Phan Thanh Phouc, youngest brother of Kim Phuc, Kim Phuc, and Kim’s cousins Ho Van Bon, and Ho Thi Ting. Behind them are soldiers of the Vietnam Army 25th Division.

In this Oct. 15, 1992 file photo, President Bush, left, talks with independent candidate Ross Perot as Democratic candidate Bill Clinton stands aside at the end of their second presidential debate in Richmond, Va.

Cuban Prime Minister Fidel Castro exhales cigar smoke during a March, 1985 interview at his presidential palace in Havana. Castro, a Havana attorney who fought for the poor, overthrew dictator Fulgencio Batista’s government on Jan. 1, 1959. He defeated a U.S. attempt, known as The Bay of Pigs invasion, to overthrow his revolutionary regime on April 19, 1961. Afterwards, Cuba armed itself with Soviet nuclear missiles aimed at the United States which almost brought the world to the brink of nuclear disaster. Castro’s communist regime still exists in Cuba, 90 miles from the U.S., at the close of the 20th century.

World Heavyweight Boxing Champion, Muhammad Ali, right, is shown with Black Muslim Leader, Malcolm X, outside the Trans-Lux Newsreel Theater on Broadway at 49th Street, New York City, March 1, 1964. They had just watched a screening of films on Ali’s title fight with Sonny Liston in Miami Beach, Feb. 25.

Broward County canvassing board member Judge Robert Rosenberg uses a magnifying glass to examine a disputed ballot Friday, Nov. 24, 2000, at the Broward County Courthouse in Fort Lauderdale, Fla.

The Beatles perform on the “Ed Sullivan Show” in New York on February 9, 1964. From left, front, are Paul McCartney, George Harrison and John Lennon. Ringo Starr plays drums.

Phil Mickelson celebrates after winning the Masters golf tournament with a nine-under-par at the Augusta National Golf Club in Augusta, Ga., Sunday, April 11, 2004.

FILE - In this Feb. 18, 1964, file photo, The Beatles, from left, Paul McCartney, John Lennon, Ringo Starr, and George Harrison, take a fake blow from Cassius Clay, who later changed his name to Muhammad Ali, while visiting the heavyweight contender at his training camp in Miami Beach, Fla. Ali turns 70 on Jan. 17, 2012.

An Iraqi man comforts his 4-year-old son at a regroupment center for POWs of the 101st Airborne Division near An Najaf, Iraq Monday, March 31, 2003. The man was seized in An Najaf with his son and the U.S. military did not want to separate father and son.

In this Saturday, Feb. 1, 2003 file photo, debris from the space shuttle Columbia streaks across the sky over Tyler, Texas. A new NASA report says that the seat restraints, suits and helmets of the doomed crew of the space shuttle Columbia didn’t work well, leading to “lethal trauma” as the out-of-control ship broke apart, killing all seven astronauts. In a graphic 400-page report, NASA further studied the Feb. 1, 2003, shuttle tragedy to help them design their new shuttle replacement capsule more likely to survive an accident.

Elian Gonzalez is held in a closet by Donato Dalrymple, one of the two men who rescued the boy from the ocean, right, as government officials search the home of Lazaro Gonzalez for the young boy, in the early morning, in this April 22, 2000 file photo, in Miami.

U.S. President George Bush, left, trades looks with Lee Atwater, chairman of the Republican National Committee, as they accompany a band during a rhythm and blues concert in Washington D.C., on Jan. 21, 1989. Bush was inaugurated one day earlier.

Mrs. Jacqueline Kennedy has a chuck under the chin for her husband moments after he became president, January 20, 1961. This exclusive picture by AP photographer Henry Burroughs was taken in the rotunda of the Capitol just after President John F. Kennedy left the inaugural stand.

U.S. Marines of the 28th Regiment, 5th Division, raise the American flag atop Mt. Suribachi, Iwo Jima, on Feb. 23, 1945. Strategically located only 660 miles from Tokyo, the Pacific island became the site of one of the bloodiest, most famous battles of World War II against Japan.

The Rev. Martin Luther King Jr. is welcomed with a kiss by his wife Coretta after leaving court in Montgomery, Ala., March 22, 1956. King was found guilty of conspiracy to boycott city buses in a campaign to desegregate the bus system, but a judge suspended his $500 fine pending appeal.

President Barack Obama, second from right, salutes with Maj. Gen. Daniel Wright , right, as a carry team carries the transfer case containing the remains of Army Sgt. Dale R. Griffin of Terre Haute, Ind., who died in Afghanistan according to the Department of Defense, during a dignified transfer at Dover Air Force Base in Dover, Del., Thursday, Oct. 29, 2009.

President Bush’s Chief of Staff Andy Card whispers into the ear of the President to give him word of the plane crashes into the World Trade Center, during a visit to the Emma E. Booker Elementary School in Sarasota, Fla., Tuesday, Sept. 11, 2001.

The German dirigible Hindenburg crashes to earth, tail first, in flaming ruins after exploding on May 6, 1937, at the U.S. Naval Station in Lakehurst, N.J. The 1920s and 1930s were the golden age of dirigibles which crossed the Atlantic Ocean in about three days — faster than a ship. The Hindenburg was the largest airship ever built at 804 feet long and flew up to 85 miles per hour while held aloft by hydrogen, which was highly flammable. The disaster, which killed 36 people after a 60-hour transatlantic flight from Germany, ended regular passenger service by the lighter-than-air airships.

In this Nov. 4, 2008 file photo, President-elect Barack Obama, left, his wife Michelle Obama, right, and two daughters, Malia, 7. and Sasha, 10, wave at the election night rally in Chicago.

A member of the Arab Commando group which seized members of the Israeli Olympic Team at their quarters at the Munich Olympic Village September 5, 1972 appears with a hood over his face on the balcony of the village building where the commandos held several members of the Israeli team hostage.

U.S. soldiers of Pennsylvania’s 28th Infantry Division march along the Champs Elysees, the Arc de Triomphe in the background, on Aug. 29, 1944, four days after the liberation of Paris, France. World War II began in September 1939 with Adolf Hitler’s invasion of Poland. He launched the Holocaust and history’s most destructive war, leaving 17,000,000 soldiers and 60,000,000 civilians dead. Germany surrendered on May 7, 1945.

Democratic presidential hopeful Bill Clinton addresses the media as U.S. Rep. Joseph Kennedy, D-Mass., looks on at a Boston campaign stop the evening of April 28, 1992.

Construction workers take a lunch break on a steel beam atop the RCA Building at Rockefeller Center, New York, Sept. 29, 1932. In the background is the Chrysler Building.