User: What exactly was Apollo 11?
Assistant: Apollo 11 was the fifth manned mission of the United States Apollo Program and the first human landing on the Moon in history. Neil Armstrong, Edwin Aldrin, and Michael Collins were the astronauts on this mission. On July 21, 1969, astronaut Neil Armstrong, soon followed by his colleague Edwin "Buzz" Aldrin, left the first human footprint on the lunar surface, while the third member of the mission, Michael Collins, circled the Moon in the command module for nearly two hours. "One small step for a man, one giant leap for mankind," Armstrong said as he set foot on the moon, became one of history's most famous quotes.