The world's largest coral reef and the largest living structure on the planet, the Great Barrier Reef is incredibly rich and diverse, and home to hundreds of animals and plants.
Unfortunately, it has decreased by more than half its size because of rising temperatures in the past 30 years. Coral bleaching thanks to acid pollution is another concern, leading scientists to predict that the reefs could be completely gone by 2030.
Snorkel or scuba dive among this natural wonder before it's gone! And if you want to help, there are plenty of science groups and even a a turtle rehabilitation center that welcomes volunteers.