1968 was an absolutely horrible year for the U.S. and also many other countries, with a level of political and social upheaval that makes today's hyper-partisanship look tame: Khe Sanh and Tet in Vietnam, the assassinations of MLK, Jr. and RFK, riots (including the so-called 'police riot' at the Chicago Democratic convention), the Soviet invasion of Czechoslovakia, and so on. I was a kid at the time, and I hope this country (and I) never experiences another year like it.
Yet, it ended on a grace note; the live Christmas Eve broadcast by the crew of Apollo 8 in orbit around the moon, the first time humans had left earth orbit and visited another body in the solar system. It was, up to that time, the largest audience for any program (to be surpassed on July 20th 1969, which I missed to my everlasting regret, as I was on my first overnight camp-out. It was the first very small step for me on the way to an active outdoors life). I'm a life-long agnostic, yet I still get choked up every time I watch it or listen to the audio. I expect many stations will re-broadcast it this Xmas Eve, but just in case you miss it and/or have never seen it, here it is: https://youtu.be/ToHhQUhdyBY
Then, after they returned to Earth, NASA published the picture taken by William Anders which the late mountaineer/outdoor photographer Galen Rowell called “the most influential environmental photograph ever taken.” It was the first time the public had seen our home, it's vibrant colors contrasting with the surrounding blackness of space and floating over the barren, sterile gray surface of the moon. It changed most people's view of our place in the Universe, how rare and precious our home was, and convinced many that we needed to take better care of it. Almost everyone has seen it, if not the photo itself then on a T-shirt, mug, stamp or what have you - it may well be the most re-produced photo of all time. But it's always worth another look - 'Earthrise': https://goo.gl/images/8SJdk3
If it's clear where you are on Xmas Eve, you might want to go outside while you listen to the broadcast and look at the moon, from this good earth.