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. This helped to calculate the exact size and shape of the planet and marked an important step in the development of earth sciences and topographic mapping. The Struve is on the list of UNESCO World Heritage sites since 2005.
Both Russian triangulation points are situated on the small Hogland Island, located in the Gulf of Finland.
150 years of County Mail. A special service created for correspondence in areas that did not have government-mail. The first post office was established in the Zemstvo Vetluga County in 1865.