The U.S.Moon mission came on July 16,1969, when Armstrong, along with astronauts Buzz Aldrin and Michael Collins, climbed into Apollo 11's command module called Columbia atop a gigantic Saturn V rocket and blasted off.
The weight of the lunar module, on top of the command and service module, was the main reason why the Saturn V rockets that shot Apollo astronauts into space needed to be the tallest, heaviest and most powerful ever flown, a record they still hold.
From the seemingly insurmountable problems of getting each stage of the Saturn V to work, to the challenges of making the Command Module safe following the fire that killed the first Apollo astronauts, even the engineers would have told you at times that they didn't think it could be done.