Columbia subject headings:
Castles--Germany--Lahn River Valley--Guidebooks.
Historic buildings--Germany--Lahn River Valley--Guidebooks.
Lahn River Valley (Germany)--Guidebooks.
Palaces--Germany--Lahn River Valley--Guidebooks.
Harvard subject headings:
Castles--Germany--Lahn River Valley--Guidebooks.
Castles--Germany--Lahn River Valley--History.
Historic buildings--Germany--Lahn River Valley--Guidebooks.
Lahn River Valley (Germany)--Buildings, structures, etc.
Princeton subject headings: