Columbia was the Apollo 11 command module that carried astronauts from lunar orbit back to Earth after the first Moon landing.
Apollo 11 consisted of the command module Columbia, the lunar module Eagle, and the Saturn V launch vehicle. Neil Armstrong and Buzz Aldrin descended in Eagle, while Michael Collins remained in lunar orbit aboard Columbia. After the surface mission, Eagle’s ascent stage returned the two moonwalkers to lunar orbit.
The astronauts transferred back into Columbia before Eagle was discarded. Columbia then fired its engine to leave lunar orbit and began the journey home. It splashed down in the Pacific Ocean on 24 July 1969.
Eagle is often associated most strongly with Apollo 11 because it landed on the Moon, but it was not the spacecraft that returned the crew to Earth. Odyssey was the command module used by Apollo 13, while Endeavour was the Apollo 15 command module.