Undersea Tunnel Introduction: The main part of the Pacific Underwater World is 80 meters long. It adopts a 90- to 270-degree closed annular acrylic transparent tunnel design. An electric transmission belt carries tourists along the channel underwater, as if they are there in person. seabed. You will have a panoramic view of the colorful coral reefs, rare marine fish swimming around, and the charming landscape of marine animals and plants. Underwater World Aquarium makes your dream of roaming under the sea come true.