Cairns is a city in Australia, and it is known as the gateway to the Great Barrier Reef. In Cairns, you can go underwater without getting wet by visiting the Cairns Aquarium. But you can also go underwater in Cairns. You can visit the Great Barrier reef This is the world’s largest coral reef system, after all, a collection of just under 3000 individual reefs and 900 islands across nearly 350,000 square kilometers. You can also spend time exploring the Kuranda rainforest where the waterfalls are also located. Cairns is a seafood lover's paradise, the seafood is fresh and the best in the state.