When the time is right, the most celebrated reef on Earth turns into a snow globe as millions of coral polyps reproduce to send the next generation afloat. This incredible display disguises a harsh truth: the Great Barrier Reef is under attack. More than half of the coral here has died, with a warmer ocean bleaching vast sections. But there is still plenty to see and plenty to save. We go on assignment in a series of dives with marine biologist and National Geographic Explorer Erika Woolsey to meet the most colorful residents of this underwater jungle.

National Geographic Explorer Dr. Erika Woolsey is a marine biologist, divemaster, and virtual reality filmmaker. Her research and career have taken her to reefs all over the world and she wants to share her passion with you!