(CNN) Saturday is the anniversary of what many consider to be the greatest achievement of the 20th century.
It's been 50 years since astronaut Neil Armstrong became the first man to step on the surface of the moon. Buzz Aldrin followed him out of the Eagle lander while Michael Collins orbited the moon in the Columbia spacecraft.
Celebrations commemorating that day are planned across the country Saturday.
Whether you saw the landing as it happened on Sunday, July 20, 1969, or recently watched rare or never-before-seen footage in the documentary, "Apollo 11," produced in partnership with CNN Films, there may be some things you've forgotten or never knew about the mission.
In May 1961, President John F. Kennedy set a goal many doubted would ever happen: He wanted to land a man on the moon before the decade was over. As pointed out by Charles Beames, the executive chairman at York Space Systems, Kennedy's Moonshot was part Cold War strategy. If it was successful, it would show America's dominance in the space race.
To pull it off, the Apollo astronauts and the teams that supported them put in grueling hours of training. They were so busy that they didn't know much about the events of the 1960s unfolding outside of what they were doing. They would catch up on the Vietnam War and other headlines later.
But the work was also dangerous. On May 6, 1968, Armstrong performed his 22nd flight of Lunar Landing Research Vehicle No. 1 at Ellington Air Force Base outside Houston. Five minutes in, he lost control of the vehicle due to a loss of helium pressure and was ejected 200 feet above the ground as the vehicle crashed and burned on impact.
Later, he would say that the Eagle, the spacecraft he and Aldrin landed on the moon, handled just like the Lunar Landing Training Vehicle, which he flew more than 30 times before Apollo 11.
"That of course gave me a good deal of confidence -- a comfortable familiarity," Armstrong said at the time. "It was a contrary machine and a risky machine but a very useful one."
On July 16, 1969, the day of Apollo 11's historic launch, rows of men in shirts and ties lined the consoles inside Kennedy Space Center.
But one woman stood out -- 28-year-old JoAnn Morgan.
Morgan, who worked as an instrumentation controller for the mission, was the only woman allowed inside the firing room where NASA employees were locked during Apollo 11's historic liftoff.
Morgan needed to be in the room to alert the test team if anything went wrong, but she had to get special permission to be there. Morgan also endured obscene phone calls and had to use the men's restroom because there weren't any for women.
She went on to pave a path as one of NASA's first female engineers. After Apollo 11, Morgan's career took off. From 1958 to 2003, she continued to break barriers and became the first female senior executive at the Kennedy Space Center.
Margaret Hamilton was the software engineer who developed the onboard computer programs that powered NASA's Apollo missions, including the 1969 moon landing.
Hamilton effectively invented the term "software engineer" with her work developing the Apollo guidance computer, the lifeline for astronauts that controlled the spacecraft. The computer processor on the Apollo 11's lunar module nearly overloaded as the craft neared the moon, which could have forced Armstrong and Aldrin to abort, according to Google, which is honoring Hamilton on the lunar landing anniversary.
But the software cleared all tasks each time it neared overload, allowing the astronauts to enter the landing commands. The software's emergency preparedness is thought to have helped save the mission, Hamilton wrote.
For the 50th anniversary of the Apollo 11 mission, Google unveiled a giant tribute to Hamilton in California's Mojave Desert: More than 107,000 mirrors were positioned to reflect moonlight and form her image for one night on the grounds of the Ivanpah Solar Electric Generating System, the world's largest solar thermal power plant.
The Apollo 11 crew of Armstrong, Aldrin and Collins traveled 240,000 miles in 76 hours to reach the moon. Collins remained in the spacecraft, Columbia, while Armstrong and Aldrin headed to the lunar surface in the Eagle.
As Aldrin and Armstrong approached, Armstrong had to take control and navigate beyond the targeted landing spot. Boulders littered the area, and even though they were running dangerously low on fuel, Armstrong piloted the lander like a helicopter and landed in the perfect spot, all while alarms sounded warnings. When the lunar module landed on the moon, it had less than 40 seconds of fuel left.
Years later, Apollo 11 flight dynamics team leader Jerry Bostick asked Armstrong what he would have done if Houston had called for an abort during the landing phase.
"And he said, 'Well, I probably would have said, "Say again Houston, I didn't copy that," and gone ahead and landed.' And he would have. And he would have done it. That's how much confidence that I and the other people involved had in Neil Armstrong. He could do the impossible," Bostick said.
It was this dynamic that earned Armstrong the nickname "Mr. Cool." Some people called him "First Man."
After the successful Apollo 11 flight, Collins saw another side of Armstrong as the three astronauts embarked on a trip around the world to talk about their experiences. Armstrong was their spokesman.
"But what people maybe don't know about First Man was that First Man was one marvelous proponent of the virtues of the United States and spread those all over the globe," Collins said.
The historic moment of Armstrong stepping on the moon roughly six hours later was actually quite blurry as it was seen on TV. The shot came from a camera attached to the lander.
But what many don't know is that Aldrin was filming Armstrong, too; he captured those monumental steps from above, while inside the lander, looking down the ladder at Armstrong.
Apollo fans and experts have long known about this angle. But the public hasn't previously seen it uncut and in high-resolution, a view that expands our knowledge of the mission. It can be seen in the "Apollo 11" film.
And then there are the photos. While the lunar surface looks quite alien up close, some of the most breathtaking images were captured when the astronauts turned the camera back to the view of Earth from space.
"Strangely enough, it looks fragile somehow," Collins said. "You want to take care of it. You want to nurture it. You want to be good to it. All the beauty, it was wonderful, it was tiny, it's our home, everything I knew, but fragile, strange."
While Aldrin and Armstrong landed on the moon, Collins kept circling it. Once Armstrong and Aldrin were finished, he would rendezvous and dock with the Eagle after it left the lunar surface.
Collins was often called "the loneliest man" once he returned to Earth, but he didn't feel that way -- even when he lost contact with Mission Control during his flybys on the far side of the moon.
"It was a happy home. I liked Columbia," he said. "It reminded me, in a way, of almost like a church or a cathedral. It had the apse, the three couches, and then you went down into where the altar was. That was the guidance and navigation system. And it was laid out almost like a cathedral. And I had hot coffee. I had music I could play if I wanted to. I had people to talk to on the radio, sometimes too many people talking too much on the radio. So I enjoyed that interlude. Being by myself in a machine up in the air somewhere was not unknown to me, and so everything was working well within Columbia, and I enjoyed it."
The first meal eaten in space was in the spring of 1961 by Russian cosmonaut Yuri Gagarin. He had pureed meat in a squeezable toothpaste-style tube, followed by a tube of chocolate sauce.
The Apollo 11 astronauts, meanwhile, had more than 70 food items to choose from. Among the foods that were eaten on the surface of the moon in the lunar module were beef stew, bacon squares, date fruit cake and grape punch.
Astronauts roaming the lunar surface also had drinking devices with water installed in their space suits, and if they were peckish they could nibble on the high nutrient food bar in their helmet.
The full triumph of Apollo 11 doesn't just belong to the astronauts. It also includes the 400,000 people that supported the mission across the country, mainly at Johnson Space Center in Houston and Kennedy Space Center in Cape Canaveral, Florida.
Young college graduates flocked to NASA after Kennedy's 1961 speech.
During Apollo 11, everyone who could possibly be needed or called upon during the mission was in a room at Cape Canaveral or Houston. They each had a specific task. And they all wanted to be there. They jockeyed for places to plug in their headsets and sat on steps.
"It was a can-do attitude," said Bostick, the flight dynamics team leader. "We were very sober and somber in what we were doing. We took it very seriously. We worked very hard. But at the same time it was fun, we really didn't think of it as a job, even though we were working 12 hours a day at least, six days a week. We didn't understand the magnitude of what we were doing."
The small room depicted in movies often shows team leaders sitting at consoles and staring at monitors.
But to accommodate the thousands of people needed, team members were in various control rooms, staff support rooms, back rooms, simulators, computing complexes and the projection room known as the "batcave."
Over the years, Apollo Mission Control and its surrounding rooms fell into disrepair. Recently, it was restored and reopened. Apollo flight controllers worked on the project to make sure it was authentic -- down to the carpet, wallpaper and even the cigarette butts in the ashtrays.
Art was a priority for NASA's second administrator, Jim Webb. He established NASA's art program in 1962 and allowed artists to start coming to the agency in 1963. He saw a need for art to capture the history that was being made and portray it for the American people. The artists were given free rein.
Norman Rockwell's famous painting of astronauts Gus Grissom and John Young originated during the early days of the program, in 1965. Andy Warhol painted a silkscreen series of Aldrin standing on the moon next to the American flag.
"The Apollo program made space accessible to us," said Mason Peck, former NASA chief technologist and professor of mechanical and aerospace engineering at Cornell University. "Those brief visits to the moon set a high bar for NASA and for all space exploration since."
In order for Apollo to be possible, NASA had to build a complex system. Spaceflight navigation had to be configured. Although there was a foundation of the mechanics of flight in the military, space was new territory. Everything was new. Apollo even helped trigger the formation of planetary science as its own field.
"It really built a infrastructure that didn't exist," said Marshall Smith, NASA's director of human lunar exploration. The program created a boost for technology and economy and allowed for the return of lunar samples to Earth, enabling a better understanding of our solar system's history."
The Apollo program, which saw 12 men walk on the surface of the moon, was shuttered after the final flight of Apollo 17, in 1972. But by 2024, NASA vows to land the first woman on the moon with the Artemis program.