Columbia subject headings:
Architecture--Designs and plans.
Architecture--Germany--Essen--History--21st century.
Essen (Germany)--Buildings, structures, etc.
Harvard subject headings:
Architects--Germany--Essen.
Artists--Germany--Essen.
Essen (Germany)--Buildings, structures, etc.
Outdoor sculture--Germany--Essen--Exhibitions.
Public art--Germany--Essen--Exhibitions.
Princeton subject headings: