Columbia subject headings:
Church buildings--Germany--Cologne--Pictorial works.
Photography--Germany--Cologne--History--19th century.
Harvard subject headings:
Church architecture--Germany--Cologne--Pictorial works.
Cologne (Germany)--Buildings, structures, etc.--Pictorial works.
Princeton subject headings:
Church architecture--Germany--Cologne--Pictorial works.
Cologne (Germany)--Buildings, structures, etc.--Pictorial works.