PJM5+Q5 Kaliningrad, Kaliningrad Oblast, Russia
Fort No. 1a "Gröben" (German Groeben) is a fortification structure of the fortress city of Königsberg, one of the small forts, an intermediate fortification of the fort belt "Night Pillow of Königsberg," named after the Prussian General Karl von Gröben, a participant in the Battle of Preussisch Eylau in 1807. It is a small fort, surrounded by a moat, with a large gorge barracks and several independent casemates. On the territory of the fort were warehouses and the arsenal of the 1st Tank Division (military unit 18885), military town No. 79. For some time after World War II, it was used as an arsenal warehouse, and in 2009 everything was disbanded. Currently, the fort is an object of the Ministry of Defense, and access to the territory is closed. The external condition of the building is, of course, depressing — time takes its toll.
Source:
https://ru.wikipedia.org/wiki/Форт_№_1a_—_Грёбен
https://urban3p.ru/object11922