Moon is the only natural satellite to Earth.
With 3476 km diameter, Moon is the fifth largest satellite of the Solar System. Moon is over a quarter of the diameter of the Earth and it is about 1/81 Earth mass.
Neil Armstrong and Buzz Aldrin was first two persons who stepped on moon. Neil Armstrong was the mission commander of Apollo 11 moon landing mission. Neil Armstrong and Buzz Aldrin spent two and half hour on lunar surface. Michel Collins remained in the orbit of the moon to take care of the command module when Armstrong and Aldrin was on moon.