Deep in the South Pacific, scientists have explored a rare stretch of pristine corals shaped like roses off the coast of Tahiti. The reef is thought to be one of the largest found at such depths and seems untouched by climate change or human activities.

Laetitia Hdouin said she first saw the corals during a recreational dive with a local diving club months earlier.

When I went there for the first time, I thought, Wow we need to study that reef. Theres something special about that reef, said Hdouin, a researcher at the French National Center for Scientific Research in Moorea, French Polynesia.