Cisternerne – The Cisterns in Søndermarken

From lifesaving reservoir to underground art temple

Cisternerne lies under Frederiksberg Hill in Søndermarken park, in chambers that once formed a crucial part of Copenhagen’s 19th‑century drinking water system. Excavation started in 1856 and the cistern was completed three years later, giving the growing city the capacity to store around 16 million litres of clean water in brick‑lined tanks safely away from the polluted surface. For decades the structure helped solve the city’s water shortages, but by 1933 newer systems had taken over and the cisterns were removed from the drinking water network. The vast space remained flooded until the early 1980s, when it was finally drained and left as an empty subterranean cathedral of brick, concrete and slowly forming mineral deposits.

An immersive space for contemporary installations

In 1996 the underground reservoir was reborn as an exhibition venue during Copenhagen’s year as European City of Culture. A collaboration between the City of Frederiksberg and curator Max Seidenfaden first presented it as a museum of modern glass art, taking advantage of the reflections in the residual water and polished brick vaults, before it evolved into a broader contemporary art space. Today Cisternerne is part of Frederiksberg Museums and each season a single artist or curatorial team is invited to create an all‑encompassing installation across the entire complex. Works often use water, sound, mist, light projections and sculptural interventions, responding directly to the architecture, the darkness and the echoing acoustics. Rather than a collection of objects, the site offers a total environment that you move through slowly, letting eyes adjust and senses recalibrate.

A man‑made dripstone cave beneath the park

Because the cistern sits under a park, water from the soil above still seeps through hairline cracks in the concrete roof. Over many decades this mineral‑rich moisture has formed delicate stalactites and stalagmites along ceilings, pillars and walls, creating what is often described as Denmark’s only real dripstone cave. The formations are fragile reminders that nature is gradually reclaiming this feat of engineering. Humidity here hovers close to 100%, and the temperature remains around 8–10°C year‑round. The air smells faintly of wet stone and earth, while occasional pools or thin sheets of water underfoot mirror columns and artworks. It is both an industrial relic and a living geological process, with decay woven into the experience as an aesthetic element.

Atmosphere, light and sound under Frederiksberg Hill

Stepping down from daylight through the modest glass entrance on the surface, you enter a semi‑dark labyrinth of long aisles and rhythmic rows of columns. Subtle lighting picks out arches and surfaces, leaving other corners in deep shadow. Sounds are amplified: footsteps on raised walkways, the distant drip of water, or a low musical score designed as part of an exhibition. Depending on the current installation you might encounter shallow water crossed by narrow pathways, projected images playing on mist, or sculptural works that emerge slowly as your eyes adjust. The sense of distance is distorted; what looks near may be separated by water, and reflections blur the boundary between architecture and artwork. It is an environment that encourages slow exploration and a heightened awareness of movement and sound.

Planning your visit inside the cisterns

Cisternerne is typically open during the exhibition season from spring to late autumn, with a pause for refurbishment between large installations. Admission is charged, with reduced rates for students and free entry for children, and visits are self‑guided at your own pace. Because of the constant chill and dampness, warm layers and sturdy, closed shoes are recommended even on hot summer days above ground. Access is largely level, with lift and ramp solutions to reach the underground hall, though lighting is intentionally low and surfaces can be wet, which some visitors may find challenging. The entrance is set in the greenery of Søndermarken, across from Frederiksberg Palace and close to the zoo, making it easy to combine time in the park with an hour or two immersed in this otherworldly underworld of water, art and slow‑forming stone.