The German mathematician and physicist Carl Friedrich Gauss, knowing that a triangle in a curved space does not have a sum of 180 degrees, measured the angles at the vertices of the three Brocken mountains in the Harz (Northern Germany), the Inselberg in Thuringia, and Hohen Hagen near Dransfeld, southwest of Göttingen. The sum was 180 degrees and 15″ (arc seconds). Further proof of the curvature of the Earth.
