I discovered this underground gallery on my first visit to Copenhagen with the 2018 ScanDesign study tour. Every year a new exhibit is installed in the old cisterns in Søndermarken. To see this year's exhibit by Tomás Saraceno, visitors row a boat through the three chambers to visit sculptures, projections, and webs, all beautifully lit and reflecting in the flooded cisterns.
Cisternerne
Tomás Saraceno: Event Horizon