Columbia subject headings:
Harvard subject headings:
Emscher River (North Rhine-Westphalia, Germany)--In art--Exhibitions.
Installations (Art)--Germany--Exhibitions.
Landscape architecture--Germany--Exhibitions.
Observatorium (Group of artists)--Exhibitions.
Sculpture, Modern--21st century--Exhibitions.
Princeton subject headings:
Emscher River (North Rhine-Westphalia, Germany)--In art--Exhibitions.
Installations (Art)--Germany--Exhibitions.
Landscape architecture--Germany--Exhibitions.
Observatorium (Group of artists)--Exhibitions.
Sculpture, Modern--21st century--Exhibitions.