Fort Louvois in Bourcefranc-le-Chapus

Fort Louvois, known locally as Fort Chapus, is located in Bourcefranc-le-Chapus, department of Charente-Maritime, France. It was built between 1691 and 1694 during the reign of Louis XIV. The fort sits opposite the citadel of Château d’Oléron on the island of Oléron. Its construction was extremely difficult due to the islet being made of shellfish and mud. The fort was designed by François Ferry and resembles Fort Risban at Calais or Grand Risban at Dunkirk. After the completion of the arsenal at Rochefort in 1666, Louis XIV wanted to create a chain of fortifications on the coast of Aunis and Saintonge. Fort Louvois was the last fort commissioned under Louis XIV. Construction started after Louis Louvois’s death in 1691, and Vauban took over the project. Vauban modified the design to create a simpler and cheaper fort. Since 1972, the fort has been the site of a museum of oyster farming.

Sources: Wikipedia, OpenStreetMap, Wikidata, Wikimedia Commons