Sapporo Maruyama Zoo in Sapporo, Japan, is about to launch a new polar bear exhibit, with the new facility doubling as a specialist breeding facility for Japan’s zoos.

The largest polar bear exhibit in Japan, the new facility – which is five times the size of the zoo’s existing habitat – will host four polar bears from overseas zoos in their new home.

Costing ¥2.3bn (US$21.6m, €17.5m, £15.6m) to build, the enclosure offers more than 500sq m (5,400sq ft) of exhibition space for every polar bear, with a 3m (9.9ft) deep pool 20 times bigger than the animals’ previous habitat at the zoo. Rising over two storeys, the enclosure has 1,500sq m (16,000sq ft) of additional space dedicated to polar bear breeding.

In addition to raising the issues facing the polar bear as climate change takes effect in the Arctic Circle, an exhibition as part of the new facility will tell visitors about the ecology of a polar bear.

The facility’s main attraction, is an 18m (59ft) walk-through underwater tunnel, which allows visitors to see the bears up close as they swim in the pool. Creating an Arctic experience, visitors will also be able to see seals in an adjacent pool, with the walkthrough experience looking at both enclosures.

Opened in 1951, Sapporo Maruyama Zoo is the oldest zoo in the Hokkaido region of Japan. Covering 22.5ha (225,000sq m), the zoo is home to 168 different species and 737 animals. The new polar bear enclosure will officially open to visitors at 11am tomorrow (13 March).