"Did you know I took the first space selfie during Gemini 12 mission in 1966? BEST SELFIE EVER" - Buzz Aldrin via Twitter.
Gemini 12 was the last of the Gemini missions where Buzz Aldrin and Jim Lovell "photographed star fields, retrieved a micrometeorite collector and... demonstrated the feasibility of extravehicular activity" (a.k.a. spacewalk), among other tests. Gemini 12 wasn't the first spacewalk, but it's success was credited to Aldrin's extensive underwater neutral buoyancy training, which was new to NASA's missions.
Project Gemini tested the space travel techniques that laid the foundations for the Apollo missions and man's landing and exploration of Earth's moon.
Underwater neutral buoyancy training. Source: www.spacefacts.de
Jim Lovell (left) and Buzz Aldrin (right) on the way to the Titan II GLV rocket. Source: Wikipedia
The Titan II GLV blasting off from Cape Canaveral. Source: www.spacefacts.de
Buzz Aldrin during his extravehicular activity (EVA). Source: Wikipedia
The Gemini crew returning to Earth. Source: www.spacefacts.de