Pristine coral reef discovered off the coast of Tahiti

Marine explorers have discovered a giant coral reef at depths of 30m off the coast of Tahiti, French Polynesia.

The structure stretches over 3km along the sea bed and is one of the largest discovered at that depth, says the United Nations Educational, Scientific and Cultural Organization, which led the mission.

Dr Julian Barbiere, from Unesco, said there were probably many more of these ecosystems "we just don't know about".
"We should be working to map them and to protect them," he said.