Updated

The year was 1969. The turbulent time in America saw troops fighting in Vietnam, and a nation dealing with the assassinations of President John F. Kennedy, killed in 1963, and Robert Kennedy and Martin Luther King Jr., both murdered in 1968.

Then came that one small step.

Forty-five years ago today, 500 million people around the world witnessed American astronauts Neil Armstrong, Edwin "Buzz" Aldrin and Michael Collins as they embarked on the Apollo 11 mission to the moon.

Apollo 11 landed on the moon on July 20, 1969, and six hours later Armstrong was the first man to step on the moon's surface, delivering those iconic words: "One small step for man, one giant leap for mankind."

LISTEN TO ARMSTRONG'S HISTORIC WORDS.

Armstrong, during the trailblazing mission, spent a little more than two hours outside the spacecraft, which was piloted by Collins. Aldrin spent slightly less time than Armstrong on the moon's surface, and together the men collected almost 50 pounds of lunar material to return to the Earth, according to the NASA website.

[pullquote]

The mission officially began at about 9:32 a.m. (ET). the morning of July 20, 1969, when the engines fired and Apollo 11 cleared the tower.

About 12 minutes later, the crew was in Earth orbit.

After one and a half orbits, Apollo 11 gets a "go" for what mission controllers call "Translunar Injection" -- in other words, it's time to head for the moon. Three days later the crew is in lunar orbit. A day after that, Armstrong and Aldrin climb into the lunar module Eagle and begin the descent, while Collins orbits in the command module Columbia.

[youtube S9HdPi9Ikhk]

When it comes time to set Eagle down in the Sea of Tranquility, Armstrong improvises, manually piloting the ship past an area littered with boulders. During the final seconds of descent, Eagle's computer is sounding alarms.

It turns out to be a simple case of the computer trying to do too many things at once, but as Aldrin will later point out, "unfortunately it came up when we did not want to be trying to solve these particular problems."

When the lunar module lands at 4:18 p.m ET, only 30 seconds of fuel remain. Armstrong radios "Houston, Tranquility Base here. The Eagle has landed."
Mission control erupts in celebration.

According to reports at the time, Aldrin described the lunar surface as "magnificent desolation."

The astronauts leave behind an American flag, a patch honoring the fallen Apollo 1 crew, and a plaque on one of Eagle's legs. It reads, "Here men from the planet Earth first set foot upon the moon. July 1969 A.D. We came in peace for all mankind."

The crew splashed down off Hawaii on July 24.