Berlin Fortress built
1650 CE.
Shown on the map at 52.517°, 13.396°.
The Berlin Fortress (German "Festung Berlin") was the fortification of the historic city of Berlin. Construction started in 1650. The ramparts, walls, moats and glacis of the 17th-century bastion fort ran around the historic city limits. The demolition of its ramparts began in 1740.
Text from the Wikipedia article Berlin Fortress, licensed CC BY-SA 4.0.