The Geeraard de Duivelsteen is a 13th century gothic architecture building in Ghent, Belgium. It served as defense of the Portus Ganda, the city's port.
Wikipedia https://en.wikipedia.org/wiki/Geeraard_de_Duivelsteen
Info https://visit.gent.be/en/castle-gerald-devil?context=tourist
Address Geraard de Duivelstraat 1, 9000 Gent, Belgium
Coordinates 51°3'7.567" N 3°43'42.389" E