Struve Geodetic Arc
Astronomer Friedrich Georg Wilhelm Struve's ideas about the earth's shape and size resulted in a huge arc measurement expedition whose purpose was to prove that the earth is flattened at the poles. The expedition was named "The Struve Geodetic Arc" and is regarded as one of the most significant technical and scientific achievements of its day. The Struve Geodetic Arc, a chain of survey triangulations that follow the 26 degree east longitude meridian, was measured from 1816 to 1855 and stretches 2,820 kilometres from the Arctic Ocean to the Black Sea. In 2005, the Struve Geodetic Arc was named a UNESCO World Heritage Site.
The official geodetic arc consists of 34 measuring points. Four of them are in Sweden and one of them is on Mt. Pullinki in Övertorneå municipality, Svanstein. The other tre is in Tynnyrilaki in Kiruna, Jupukka in Pajala and Perävaara in Haparanda municipalities. There is also a measuring point on Mt. Aavasaksa in the neighbouring Finnish community of Ylitornio.