North Pole
The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is defined as the point in the northern hemisphere where the Earth's axis of rotation meets the Earth's surface. It should not be confused with the North Magnetic Pole.
The North Pole is the northernmost point on Earth, lying diametrically opposite the South Pole. It defines geodetic latitude 90° North, as well as the direction of True North. At the North Pole all directions point south; all lines of longitude converge there, so its longitude can be defined as any degree value.
While the South Pole lies on a continental land mass, the North Pole is located in the middle of the Arctic Ocean amidst waters that are almost permanently covered with constantly shifting sea ice. This makes it impractical to construct a permanent station at the North Pole (unlike the South Pole). However, the Soviet Union, and later Russia, have constructed a number of manned drifting stations, some of which have passed over or very close to the Pole. In recent years, a number of studies have predicted that the North Pole may become seasonally ice-free due to Arctic shrinkage, with timescales varying from a few years to fifty years or more.
