On July 16, 1969, Apollo 11 was launched into space with three astronauts aboard: commander Neil Armstrong, command module pilot Michael Collins, and lunar module pilot Edwin E. Aldrin, Jr. Four days later, millions watched on television as Neil Armstrong climbed down a ladder and stepped onto the moon's surface. The television audience heard Armstrong say, "That's one small step for man, one giant leap for mankind." He and Aldrin left an American flag as proof of their accomplishment.