In 2009, National Geographic Pristine Seas explored the Southern Line Islands in the Pacific Ocean and found pristine coral reefs, with thriving corals and large fish abundance. But in 2015-16, an unprecedented ocean warming event killed half of the corals. The Pristine Seas team returned in 2021, hoping to see some signs of recovery. What they found instead was the most spectacular recovery of coral reefs ever witnessed, thanks to the full protection of the reefs from human activity as a Marine