Reasons to Recommend: The Busan Aquarium is a large aquarium in South Korea. It has fish, birds, reptiles, and amphibians. There are about tens of thousands of animals. The Busan Aquarium is famous for its underground tunnel. Entering the tunnel is like being on the bottom of the sea. The fish swim across the top from both sides. It feels magical and interesting. The undersea tunnel is also popular among tourists.