​​The Saint-Pierre Bunker, located within Calais’s Saint-Pierre Park and facing the town hall, was built by the Organisation Todt for the German Navy (Kriegsmarine) during the occupation of France. Officially operational from 26 February 1941, the structure served as the Hafenkommandantur—the port command office—and was integrated into the German coastal defence network as Wn13 Park, under the authority of Küstenverteidigungsabschnitt C (KVA C), part of the KV Gruppe Calais.

​The bunker was built in reinforced concrete and measured 94 metres in length, with wall thicknesses between 1.5 and 2 metres and a 1.5-metre-thick ceiling. The building contained five gas-tight compartments, designed to maintain operational capacity in the event of a gas attack. Inside, it housed communications infrastructure—telephone, telegraph, and radio systems—that covered an area stretching from the Baie de Somme to the Scheldt estuary. It played a key role in coordinating surface units and directing coastal artillery fire, including batteries at Oldenburg, Calais, and Lindemann.

​Its internal layout included quarters for officers and enlisted personnel, a machine room, ventilation and heating systems, a telephone exchange, infirmary, armoury, and administrative offices. Additional facilities such as a mess hall, kitchen, showers, and a recreation room were built nearby. Attached to the main structure were a garage and a technical room used for storage and maintenance.

​Several naval officers commanded the site, reporting to the Seekommandant of Pas-de-Calais, Vice Admiral Friedrich Frisius. The bunker even received a visit from Grand Admiral Karl Dönitz on 23 June 1943.

​On 22 September 1944, as Canadian troops from the 3rd Infantry Division approached Calais, German personnel destroyed sensitive documents before retreating. The bunker was captured on 30 September 1944 and its central systems were destroyed by flamethrowers to prevent further use. After the war, the site was sealed until 1962, when the municipality reopened it as a museum. Since 2010, it has operated as the “Musée Mémoire 1939–1945”, preserving the wartime history of Calais and its surrounding region.