Churaumi Aquarium — Whale Shark Mega Tank

Okinawa Churaumi Aquarium houses the world's second-largest aquarium tank (after Dubai) — the Kuroshio Sea tank holding 7,500 cubic meters of water, home to three whale sharks (the world's largest fish, growing to 12 meters) and manta rays with 6-meter wingspans. The tank's 8.2m x 22.5m acrylic panel allows floor-to-ceiling viewing as the whale sharks glide past at eye level.

The aquarium is part of Ocean Expo Park, a sprawling coastal park also containing the Oceanic Culture Museum, Tropical Dream Center botanical garden, and free dolphin shows (5 times daily). Allocate a full day to cover the entire park.