The 22nd Karelian Fortified Region is a 60 km wide Soviet defensive fortified district to the north of Leningrad that was built in 1928–1932, 1938–1939, 1941–1944 and 1950–1965 in the Soviet part of the Karelian Isthmus amongst other fortified areas constructed around that time in order to defend the western borders of the Soviet Union. Wikipedia