Mannerheim's Line

Mannerheim's Line was a defensive fortification built by Finland along its border with the Soviet Union before World War II. Designed to slow or halt an invasion, it included trenches, bunkers, and obstacles. Although heavily fortified, it was never fully tested in battle because Finland, facing the Soviet attack in 1939, eventually relied on mobile defense and strategic withdrawals. The line represented Finland’s efforts to protect its independence during a period of heightened tension in the region.