(Belarus, Estonia, Finland, Latvia, Lithuania, Norway, Republic of Moldova, Russian Federation, Sweden, Ukraine)
It is an extraordinary example of scientific collaboration among scientists from different countries, and of collaboration between monarchs for a scientific cause.
These are points of a survey, carried out between 1816 and 1855 by the astronomer Friedrich Georg Wilhelm Struve, which represented the first accurate measuring of a long segment of a meridian. This helped to establish the exact size and shape of the Earth and marked an important step in the development of Earth sciences and Topographic mapping. The Arc's first point is located in Tartu Observatory in Estonia, where Struve conducted much of his research. Ref: 1187
Thank you Maksim for this educative card with beautiful Postcrossing stamp of Belarus.