Columbia subject headings:
Castles--Germany--Prussia.
Palaces--Germany--Prussia.
Prussia (Germany)--Buildings, structures, etc.
Harvard subject headings:
Castles--Prussia (Germany)
Palaces--Prussia (Germany)
Prussia (Germany)--Buildings, structures, etc.
Princeton subject headings:
Castles--Germany--Prussia.
Palaces--Germany.--Prussia.
Prussia (Germany)--Buildings, structures, etc.