The Challenge: Rivals III is a season of American Ninja Warrior.
The Struve Geodetic Arc is a chain of survey triangulations stretching from Hammerfest in Norway to the Black Sea , through ten countries and over 2,820 km , which yielded the first accurate measurement of a meridian .. Geodetic. Geodesy. Hammerfest. Hammerfest. Black Sea. Black Sea. The chain was established and used by the German-born Russian scientist Friedrich Georg Wilhelm von Struve in the years 1816 to 1855 to establish the exact size and shape of the earth .. Friedrich Georg Wilhelm von Struve. Friedrich Georg Wilhelm von Struve. exact size and shape. Reference ellipsoid. earth. earth. At that time , the chain passed merely through two countries  : Union of Sweden-Norway and the Russian Empire .. Union of Sweden-Norway. Union between Sweden and Norway. Russian Empire. Russian Empire. The Arc 's first point is located in Tartu Observatory in Estonia , where Struve conducted much of his research .. Tartu Observatory. Tartu Observatory. In 2005 , the chain was inscribed on the World Heritage List as a memorable ensemble of the chain made up of 34 commemorative plaques or built obelisks out of the original 265 main station points which are marked by drilled holes in rock , iron crosses , cairns , others .. others. Struve Geodetic Arc#Chain. World Heritage List. World Heritage List. Measurement of the triangulation chain comprises 258 main triangles and 265 geodetic vertices .. The northernmost point is located near Hammerfest in Norway and the southernmost point near the Black Sea in Ukraine .. Hammerfest. Hammerfest. Black Sea. Black Sea. This inscription is located in ten countries , the most of any UNESCO World Heritage .