National Moon Day is celebrated on July 20 each year to commemorate the historic Apollo 11 mission, during which astronauts Neil Armstrong and Buzz Aldrin became the first humans to walk on the Moon in 1969. This day honors the achievements of space exploration and the scientific advancements that have come from studying our lunar neighbor. The celebration encourages people to learn more about the Moon, its phases, and its significance in various cultures. Activities may include educational programs, stargazing events, and discussions about future lunar missions, such as those planned by NASA and other space agencies.