The Apollo program was a NASA mission to land humans on the Moon from 1969 to 1972. Six of the missions (Apollo 11, 12, 14, 15, 16, and 17) were successful in landing astronauts on the Moon. There were also many unmanned Moon landings. The Apollo missions followed NASA's Mercury and Gemini missions.
The Apollo 11 mission was the first successful manned landing. Neil Armstrong and Buzz Aldrin walked on the surface of the Moon on 20th July, 1969. Michael Collins stayed inside the spacecraft, in orbit around the Moon, to make sure all three astronauts made it safely back to Earth. They landed in the Pacific Ocean on 24th July.
When stepping out onto the surface of the moon, Neil Armstrong famously said: "That's one small step for a man, one giant leap for mankind."
The Apollo mission is the only space mission to have sent astronauts beyond low Earth orbit, above an altitude of 2,000 km. Apollo 8 was the first manned spacecraft to orbit another body, when it circled the Moon in 1968. The missions have brought 400 kg of rock and soil from the Moon's surface to Earth for scientific investigation.