TAMPA, Fla. (WFLA) — On Christmas Eve, 1968, millions of people around the world tuned in to watch NASA’s Apollo 8 astronauts Frank Borman, Jim Lovell and Bill Anders become the first humans to orbit another world. The moon.

While their command module orbited over the lunar surface, the astronauts beamed back now-iconic images of the moon and Earth.

According to NASA.gov, the astronauts were told that “on Christmas Eve we would have the largest audience that had ever listened to a human voice,” Borman recalled during the 40th anniversary celebration in 2008. “And the only instructions that we got from NASA was to do something appropriate.”

The mission was also famous for the iconic “Earthrise” photo captured by Anders which instilled a new perspective of the blue planet.

Anders has gone on record saying despite all the training for the moon exploration, the astronauts ended up discovering Earth.

After circling the moon 10 times on Christmas Eve, the crew was on schedule to return home. A day later, on Christmas morning, mission control anxiously waited for word that Apollo 8’s engine burn to leave the lunar orbit had succeeded.

They soon got confirmation when Lovell radioed, “Roger, please be informed there is a Santa Claus.”