Great Barrier Reef

Cruising the Great Barrier Reef offers an up-close look at the world's largest living organism. Tiny creatures called polyps, working together in billions-strong colonies, built the Great Barrier Reef into a network of coral reef systems and tropical islands so large it's visible from space. As the ship sails through azure passages, you'll spot the reefs themselves brimming with tropical fish, sea turtles and other marine life.