Wikipedia
Cisternerne
The Cisterns ( English: The Cisterns is a museum in Copenhagen, Denmark. The Cisterns is an integral part of The Frederiksberg Museums, acting as a venue for art exhibitions and other events where the singularity of its architecture and atmosphere remains a core attraction.
The Cisterns: A Cave within a City Located under Frederiksberg Hill in the heart of Søndermarken Park, The Cisterns is the only dripstone cave in Denmark. The natural formation of stalactites and stalagmites are not uncommon for concrete structures, yet none anywhere can offer the sheer magnitude and diversity of those found here.
In February 2009 Forbes listed Cisternerne as one of the more unusual exhibition spaces in Europe.