Osaka Aquarium Kaiyukan

Kaiyukan opened in 1990 and was built around one idea: a single tank nine metres deep holding 5,400 cubic metres of water, with the whole building spiralling down around it. You take an escalator to the eighth floor, then walk down through fourteen zones arranged as a circuit of the Pacific Rim, from Japanese forest to Aleutian rocks to Monterey Bay to Antarctic ice, and the central tank keeps reappearing beside you at a different depth each time. It is a good piece of design and it still works thirty-five years later.

The whale sharks in that tank are the headline and also the difficult part. They are the largest fish in the sea, kept in an enclosure that no aquarium can really make big enough, and Kaiyukan's practice is to return them to the ocean when they outgrow the tank and take in younger ones. Whether that is acceptable is a fair question to think about while you are looking at them. They are extraordinary to see up close.

Elsewhere: sea otters, capybaras, penguins on ice, jellyfish in dark cases, and a touch pool where you can put a hand on rays and small sharks.

Tickets are around 2,700 yen for adults, which is high, and weekends and school holidays are very busy. Late afternoon entry, after about four, is calmer and the lighting shifts as the day ends. Allow two to three hours.

It sits on Tempozan by Osaka Bay, next to a large ferris wheel and a market building, and the Osaka Bay ferry across to Universal Studios leaves from the pier outside. Chuo subway line to Osakako, then five minutes on foot.