The North Pole is a point on Earth's surface some 750 km north of Greenland through which passes Earth's axis of rotation. It does coincide with Earth's North Magnetic Pole, which is over 1,000 km away. The Pole lies roughly at the center of the Arctic Ocean, which there is permanently ice-covered, and experiences days and nights each of six months. It was first reached by Robert Peary on 6 April 1909. See also celestial sphere.