Events in the southern U.S. state of Florida and Washington, D.C. Tuesday kicked off observances marking the 50th anniversary of the historic Apollo 11 mission to the moon.
Apollo astronauts - Neil Armstrong, Buzz Aldrin and Mike Collins - blasted off from the Kennedy Space Center in Florida 50 years ago on the towering Saturn Five rocket to begin their journey to the moon.
Washington's Smithsonian Air and Space Museum observed the day by unveiling a display featuring the restored space suit worn by Armstrong, the first person to set foot on the moon.
U.S. Vice President Mike Pence presided at the event, along with NASA Chief Jim Bridenstine and Armstrong's son, Rick. Armstrong died in 2012.
As part of the Apollo anniversary observance, an actual-size image of the Saturn Five will be projected on the side of the Washington Monument on the National Mall Tuesday through Thursday night.
Meanwhile, one of the surviving Apollo astronauts, Mike Collins, returned to the Kennedy Space Center Tuesday near the exact spot where he and his fellow astronauts blasted off for the moon.
Collins, now 88, said as they lifted off from the earth that day, the astronauts were well aware the whole world was watching:
"We crew felt the weight of the world on our shoulders. We knew that everyone would be looking at us, friend or foe. And we wanted to do the best we possibly could, put our best foot forward and that required a great deal of work on our part," he said.
Collins, who remained in the Apollo command module while his fellow astronauts Aldrin and Armstrong landed on the moon, said he was very happy being alone in the spacecraft as it orbited the moon. Rather than return to the moon, Collins said he thinks future space missions should concentrate on landing on Mars.
Aldrin, 89, had been expected to join Collins at Cape Kennedy, but unexpectedly canceled without explanation.