I missed an important anniversary last month -- the "Earthrise" photograph taken on December 24, 1968 during the Apollo 8 mission. Here's a terrific video from NASA reconstructing how, where, precisely when it happened, using data from the Lunar Reconnaissance Orbiter (LRO). It includes a lengthy recreation of what it would have looked like to be on Apollo 8 and looking out at the Earth rising for the first time. Amazing.
My favorite part is hearing the astronauts talk through how to get the right exposure ("1/250 at f/11" is the shutter speed and aperture) and try different settings. The shot came out brilliantly.