Fifty years ago Friday, on Dec. 21, 1968, Apollo 8 lifted off, marking the first time humans left low Earth orbit and flew to the moon.

This was the second manned spaceflight of the Apollo program, and it was a nerve-wracking and remarkable flight that captured the world's attention. The mission capped a difficult and conflict-filled year in the U.S., offering a rare moment when people could feel good about their planet.

Any trip to space is risky. But a mission to the moon, nearly a quarter-million miles from Earth, was something else. There were many things that could go wrong and many unknowns about this first trip. But on Christmas Eve 1968, the capsule made it to lunar orbit. //

There was also an unexpected moment during the 20 hours they circled the moon. As they focused on the lunar surface below, something else caught the crew's attention.

"Oh my God, look at that picture over there! It's the Earth coming up. Wow, is that pretty!" exclaimed Anders.

Anders rushed to snap a picture of the Earth, rising above the barren lunar landscape. The "Earthrise" image remains one of the most famous ever taken in space, and Anders says it forever changed the way people think about where we live.

"The only color that we could see and contrasted by this really unfriendly, stark lunar horizon, made me think, 'You know, we really live on a beautiful little planet,' " he says. //

In an interview with NPR earlier this year, Borman, the mission commander, noticed the same thing. "The only telegram I remember out of all the thousands we got after Apollo 8 said, 'Thank you Apollo 8 you saved 1968,' " he said.