It spreads over three kilometers and is more than 30 meters deep. In December 2021, a huge intact coral reef was discovered off Tahiti island (The Society Islands, French Polynesia). This discovery was made as part of a scientific research mission supported by UNESCO. The reef is made up of corals in the shape of giant roses glued together. It seems to be in very good health, which surprises scientists given its location: the reef is located in the twilight zone of the ocean where light penetrates little. According to UNESCO, it is one of the largest coral reefs in the world to be more than 30 meters deep. Photo credit: Alexis Rosenfeld