The largest aquarium in Japan and the single biggest draw in Okinawa Prefecture, about an hour north of Onna on the Motobu Peninsula. The Kuroshio Sea tank holds 7,500 cubic metres of water with whale sharks and manta rays in it, seen through an acrylic wall two feet thick. Alongside it are the world's largest living coral exhibit and a deep-sea gallery of bioluminescent species. Adults 2,180 yen, open 08:30 to 18:30, no advance booking needed.