Thousands of people have been celebrating the 50th anniversary of the first moon landing.
On 20 July 1969, the Eagle module from Apollo 11 landed at Tranquility Base.
Hours later, at 21:56 CT (0356 GMT), Neil Armstrong made history by becoming the first person to walk on the moon.
Originally inspired by the US's Cold War rivalry with the Soviet Union, the mission is now remembered as an iconic moment for stargazers all over the world.
'We're breathing again'
Nasa marked the anniversary by streaming footage of the launch online, giving a new generation a chance to see the historic moment that was watched by half a billion people 50 years ago.
At the moment the spacecraft landed, Apollo 11 commander Armstrong said: "Houston, Tranquility Base here. The Eagle has landed."
A young girl looking at an exhibit at an anniversary event at the Space Centre Houston Charlie Duke, the capsule communicator, responded from mission control in Houston: "Roger, Tranquility. We copy you on the ground. You got a bunch of guys about to turn blue. We're breathing again."
Hours later, as he first stepped onto the moon's surface, he uttered the historic phrase: "That's one small step for man, one giant leap for mankind."
Armstrong was joined by his crewmates Buzz Aldrin and Michael Collins. All three were born in 1930, and although Aldrin and Collins are still alive, Armstrong died in 2012 at the age of 82.
Aldrin, the second person to walk on the moon, tweeted on Saturday: "Today, America put the big question to rest: We got there first. We landed on the moon with 250 million Americans watching our backs.
"The truth is: that mission belongs to all of them, and to future generations of Americans who dream to reach the moon once more."
Buzz Aldrin became the second person to walk on the moon
Michael Collins, the third crew member, told Fox News that it's "not very often" he thinks about the mission.
"I lead a quiet life," he said. "I'll be walking along down my street at night, when it's starting to get dark, and I sense something over my right shoulder - and I look up and see that little silver sliver up there and think, 'Oh, that's the moon! I've been there!'"
How the world has celebrated
Cities globally have held events to celebrate the landmark anniversary - including at Nasa's visitor centre Space Centre Houston, near the site of the Apollo 11 launch.
Military personnel put on a parachute display, and live bands performed. A New Year-style countdown will also mark the moment of Armstrong's first steps.
BDST: 0923 HRS, JULY 21, 2019