Columbia subject headings:
Aachen (Germany)--Buildings, structures, etc.
Architecture--Germany--Aachen--History--20th century.
Historic buildings--Germany--Aachen.
Public architecture--Germany--Aachen.
Harvard subject headings:
Aachen (Germany)--Buildings, structures, etc.
Architecture, Modern--20th century--Germany--Aachen.
Architecture--Germany--Aachen--History--20th century.
Architecture--Germany--Aachen--History.
Architecture--Germany--Aachen.
Princeton subject headings: