IT’S REEFS ALL THE WAY DOWN: Surprise! Another Massive Reef Is Hiding Behind the Great Barrier Reef.

The scientists called the discovery “vast,” as they’ve mapped about 2,300 square miles (6,000 square kilometers) of the reef. Each doughnut-shaped mound measures 650 to 980 feet (200 to 300 meters) across and up to 33 feet (10 m) deep at the center.

The structures form “a significant inter-reef habitat” covering a greater area than nearby coral reefs, said Mardi McNeil, lead author of the new study and a marine geoscience research student at the Queensland University of Technology.

But is the diving any good?