Den Blå Planet, Copenhagen

The Blue Planet begins before you are inside. Seen from the air, or from a plane dropping into Copenhagen Airport next door, the building is a spiral of curved arms unwinding from a central core, like water swirling into a drain. The Danish practice 3XN took the whirlpool as its idea and followed it through: the facade is clad in tens of thousands of small diamond-shaped aluminium shingles that shift in tone with the angle and the weather, the building stands on a headland on the Øresund shore ringed by a reflecting pool, and visitors enter at the eye of the vortex, a curving lobby from which the exhibits spin off along each arm.

This is the National Aquarium of Denmark, and the institution is older than its building. The original Danmarks Akvarium opened in Charlottenlund, north of the city, in 1939 and ran for 73 years; parts of the monster film Reptilicus were shot there in 1960. When it closed in 2012, most of its animals moved south to Kastrup, and The Blue Planet opened in March 2013. It is the largest aquarium in Northern Europe, holding some seven million litres of water across 53 tanks and displays, and in its first year it drew around 1.3 million visitors, twice what had been expected.

Each arm of the spiral is a different world. The Warm Ocean holds the largest tank, about four million litres, where hammerhead sharks, eagle rays and groupers glide past a panoramic window 16 metres wide and 8 metres high, with a shark tunnel running beneath. In the Rainforest a great school of piranhas circles among arapaimas and freshwater stingrays, and in the cold-water section a 15-metre bird cliff rises above a North Atlantic tank where puffins dive among cod and wolffish. The building even works with the sea outside: it is cooled with water drawn from the Øresund.

Among the residents most visitors seek out are the sea otters, which moved in during 2014 and made the aquarium one of very few places in Europe to show them. Scheduled feedings of the otters, the sharks and rays, and the reef fish give the day a rhythm, but the architecture repays attention too: step outside onto the terraces and look back at the spiral against the sound.

Getting there

The aquarium is at Jacob Fortlingsvej 1 in Kastrup, a harbourside suburb about 7 km from central Copenhagen, and just over 2 km from Copenhagen Kastrup Airport (CPH). It is close to the metro, the railway and the motorway, and has its own parking.