Ningaloo Reef, Australia
Jumping into crystalline water with the world’s biggest shark might not seem like a good idea at first but, unless you’re plankton, you’ve got nothing to worry about. Though they can grow up to 12m in length, whale sharks are gentle giants that congregate along Ningaloo Reef in Western Australia from March to August. A mass spawning attracts zooplankton, including krill and copepods, which the whale sharks feed on. Dive or snorkel in April to see a huge fish gliding serenely past you.