OSOWIEC - POLISH COMBAT SHELTER FROM 1939
Osowiec - a Polish combat bunker from 1939 located at the Rudzki Canal near the railway bridge and the Białystok-Grajewo-Ełk road on the Biebrza River, it was intended for two field guns and a heavy machine gun position. In the first days of the September 1939 campaign, it fulfilled its role. Destroyed by the German army in 1944. Currently, next to the bunker, there is an observation tower overlooking the Biebrza National Park.