Mannerheim Line

a system of former Finnish border fortifications on the Karelian Isthmus. It was named after Finnish marshal C. von Mannerheim.

The line was constructed in 1927-39; its construction was completed under the direction of Belgian General Badout, who took part in construction of the Maginot line. The Mannerheim line covered the Keksgol’m and Vyborg axes, touching Lake Ladoga and the Gulf of Finland on the flanks. It was 135 km wide on the front and up to 95 km deep and consisted of the forward defense zone (15-60 km deep); the main zone (7-10 km deep); the second zone, which was 2-15 km from the main zone; and the rear (Vyborg) zone of defense. More than 2,000 permanent pillboxes and earth-and-timber works were built and joined into strongpoints, which had two or three pillboxes and three to five earth-and-timber works apiece; the strongpoints were then joined into centers of resistance, which had three to four strongpoints each. The main zone of defense consisted of 25 centers of resistance, which had 280 pillboxes and 800 earth-and-timber works. The strongpoints were defended by permanent garrisons (from a company to a battalion in each). In the intervals between the strongpoints and centers of resistance there were positions for field troops. The strongpoints and field troop positions were covered by antitank and anti-personnel obstacles. The forward defense zone alone had 220 km of wire entanglements in 15 to 45 rows, 200 km of abatis, 80 km of granite dragon’s teeth in up to 12 rows, antitank ditches and scarps, and many minefields.

During the Soviet-Finnish War of 1939-40, Soviet troops broke through the Mannerheim line. After the war most of the remaining structures were destroyed. During World War II (1939-45), Finnish troops partially restored the structures of the Mannerheim line. In 1944, Soviet troops again broke through the Mannerheim line along the Vyborg axis, and all its fortifications were subsequently completely destroyed.