The final mission to the moon before the crew of Apollo 11 with Neil Armstrong actually landed and walked on the surface.
Apollo 10 had to be bittersweet for the crew. They flew down to within ten miles of the surface but landing was not part of the mission. The story goes that to ensure the crew did not even attempt a landing, there was only enough fuel on board for them to complete their precise mission objectives. If they broke ranks and went for a landing, they would have being stuck there !
The Apollo 10 Crew (L-R):Eugene A. Cernan, Lunar Module Pilot, Thomas P. Stafford, Commander, John W. Young, Command Module Pilot