Lanai’s Cathedrals formed thousands of years ago when lava flowed into the ocean creating expansive cavern systems. Over the years, segments of lava rock have fallen from the top and sides of the Cathedrals allowing the bright Hawaiian sun to pierce through, illuminating the caverns and highlighting the turquoise water. The well-lit chambers of the Cathedrals are large, 20-30 feet tall, and have multiple entry and exit points, making them accessible to certified divers of all levels.