Snorkel the Great Barrier Reef, Queensland

Live out your own sequel to Finding Nemo (2003) by diving into this 2,300km (1,429mi) stretch of coral reef straddling the North Queensland coast; it’s the largest coral reef system anywhere on earth. Sail, snorkel and splash around the reef from its major gateway cities Cairns and Townsville, but get in quick to catch the reef at its most colourful because warmer sea temps caused by climate change are quickly bleaching the coral.