On the grounds of Gromadzyn Stary there are numerous traces of fortifications built by the Russians and later used by the Germans.
The fortifications near the Gromadzyn Stary village in the Kolno district form a part of the so called Mołotow’s Line and they are a fragment of the Soviet Fortifications Area. They were built in the years 1940-1941. The bunkers were used during the battles with the Germans from 22 June to 25 June 1941.