The Fort de la Chartreuse, which dominates the Amercœur neighborhood of Liège in Belgium, was built between 1817 and 1823 to defend the city.
Wikipedia https://en.wikipedia.org/wiki/Fort_de_la_Chartreuse
Address (Unnamed Road), Liège 4030, Belgium
Coordinates 50°37'54.151" N 5°35'55.219" E