The Raid on Fort Douaumont

Fort Douaumont, the largest of the 19 defensive forts protecting Verdun, was built in the late 1800s and reinforced up to 1913. It had a total surface area of 30,000 m2 and was approximately 400 meters long. The fort was equipped with a 155mm rotating/retractable gun turret and a 75mm gun rotating/retractable gun turret, among other weapons. However, in 1915, the fort was stripped of most of its weaponry. On February 25, 1916, a small German raiding party of 19 officers and 79 men entered and occupied Fort Douaumont without a fight, surprising the French garrison. The German raid caused a shock to the French Army, setting the stage for a prolonged and bloody battle that lasted for months and resulted in enormous casualties on both sides.

Sources: Wikipedia, OpenStreetMap, Wikidata, Wikimedia Commons