Fort Decaen
France · built 1878
The Feste Schwerin, renamed fort Decaen by the French in 1919, is a military installation near Metz. It is part of the first fortified belt of forts of Metz and had its baptism of fire in late 1944, when Battle of Metz occurred.
Fort data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).