As the largest living organism in the world, the Great Barrier Reef is a must-see for any Australian touristAs the largest living organism in the world, the Great Barrier Reef is a must-see for any Australian tourist.Various companies offer trips out to sea to experience the natural beauty of coral,exquisite tropical fish in every color imaginable, and an incomparable underwater life.Trips range from a simple one-day taste of the reef to full-blown scuba diving certification excursions.What kind of service do the companies offer?Trips range from a simple one-day taste of the reef to full-blown scuba diving certification excursions.One day perhaps is not enough.