Columbia subject headings:
Cultural property--Protection--Germany--Essen.
Industrielle Kulturlandschaft Zollverein (Essen, Germany)
Mine buildings--Conservation and restoration--Germany--Essen.
Zollverein Mine (Germany)--History.
Harvard subject headings:
Architecture, Industrial--Conservation and restoration--Germany--Essen.
Architecture--Germany--Essen--20th century.
Essen (Germany)--Buildings, structures, etc.
Mine buildings--Remodeling for other use--Germany--Essen.
Zollverein Mine (Germany)
Princeton subject headings: