Near the station, there are two South Poles, one ceremonial and the other geographic. (There are at least two others: the South Magnetic Pole and the South Pole of Inaccessibility, defined as the spot on Antarctica and on the Earth's surface, and farthest from any ocean. Both are far from the base.) The ceremonial Pole [R] is fixed relative to the ice sheet (thus to the station) and is half-surrounded by the flags of the original signatories of the Antarctic Treaty (the USA, the UK, Norway, Belgium, France, the USSR, Japan, Argentina, Chile, South Africa, Australia, and New Zealand, with Russia taking the place of the USSR). The geographic Pole [S] (altitude 2837m/9308ft, varying slightly each year, although because of the Earth's spin it is barometrically and physiologically equivalent to 4000m) is re-measured annually on 1 January, moving about 10m (30 feet) "southwest" per year. (The model shows the station's closest New Year's Day approach to the Geographic Pole, on 1 January 2010, in the background of the photo, taken in 2011.)