The machine-gun bunker is located in downtown Puumala. Although the bunker belongs to the Ministry of Finance, Puumala is responsible for keeping it open. This concrete bunker was built in 1941 as part of the Salpa Line.
The Salpa Line was built from 1940 to 1944 as a defence line for eastern Finland. At the time, it was the largest construction site in the history of the country. Besides the machine-gun bunker in Puumala, approximately 700 concrete bunkers were built. The Salpa Line also had bunkers as living quarters, machine-gun nests, gun emplacements and 350 km of trenches.
The walls of the bunker are made of reinforced concrete and are 160–210 cm thick. The bunker has enough room for 20 individuals. In addition, it has its own well, sewerage and ventilation, which meant that it was possible to defend the bunker without outside help.
The bunker was equipped with a Maxim machine gun, a 45-mm anti-tank gun and a submachine gun. The anti-tank gun and the machine gun have been left in the bunker in Puumala.