“Although tourists aren’t allowed to climb on the islands, according to the national park laws, they gain access to the secreted beach within through a submarine tunnel that is naturally chiseled into the island’s side. When the tides recede, the top of the long passageway emerges just above the waves allowing the right amount of space to swim through James Bond-style, sans scuba gear.”
It’s certainly one of the most amazing places I’ve ever been to. And you can read all about how it was formed in this Daily Beast article. Photo Courtesy Daily Beast.