Great Blue Wild

In three decades, the waters around the remote village of Cabo Pulmo have gone from wildly biodiverse, to barren, to a bountiful and pristine haven for mighty sharks and flying rays once again. See how local fishermen ultimately turned back the clock, restoring one of the world's most majestic coral reefs.

The island nation of Palau created the first shark sanctuary and the largest marine sanctuary.

In Palau, the local economy relies on ecotourism that's sustained by strong legal support. Shark hunting is banned, giant manta rays are protected by law, and tireless efforts are made to combat the acidification an ocean ecosystem housing coral reefs. But can ambitious conservation keep pace with the scale of man-made devastation?

Raja Ampat in the Indonesian archipelago is home to diverse marine life, including manta rays.

Indonesia's marine rainforests are under threat, and rising sea temperatures and destructive fishing practices have taken a toll. However, conservation initiatives in hundreds of protected marine zones have given hope to the giant manta rays, 300 species of coral, and six of the world's seven sea turtle species that call this ecosystem home.

Fascinating creatures thrive in the muck.