Neil Armstrong was the first man to step on the moon during NASA's Apollo 11 mission on July 20, 1969. As commander of the mission, he famously declared, "That's one small step for [a] man, one giant leap for mankind," as he took his historic first step onto the lunar surface. Armstrong's achievement marked a significant milestone in space exploration and solidified the United States' position in the Space Race during the Cold War. His journey, alongside fellow astronaut Buzz Aldrin, opened doors for future lunar missions and advancements in space science.