The Apollo program was the focus of the U.S. space program from 1967 to 1972. Beginning with Apollo 11, which landed on the Moon on July 20, 1969, Apollo spacecraft landed twelve men on the Moon’s surface. Aside from gathering tremendous amounts of new information about the Moon, and bringing back 842 pounds (382 kilograms) of Moon rock, the Apollo program showed conclusively that it was possible for humans to set foot on an object in the universe other than Earth, proving that outer space is not a barrier, but a frontier.