Danish-German dike by the North Sea

Boundary marker 280. Looking into Denmark. The last boundary maker together with the first do not have a line indicating the line, but a pyramide top. They are also taller. Boundary marker says 15.6.1920, which was the date the boundary line was agreed. Jesper is eye measurring the boundary line seeing boundary marker 279. The road between marker 279 and 280 has the boundary line in the middle. If you go there without your passport, you must either go North to Højer Sluse (floodgate) or violate either Danish traffic law by driving on the left side or German imigration law.