The only way to get to Cocos Island is by boat -- and it takes more than 30 hours. Our boat, the Sea Hunter, was fully equipped and staffed to get our crew there in comfort and in first class.

Along the way, travelers pass time with movies, books, lounging and gourmet meals. But the long trip was worth it.

"There aren't too many dive trips where you spend 32 hours to get to a dive site," said the Sea Hunter's captain, David "P.J." Probert. "But the good thing is that once you're here, all the diving is done here without too much moving."

The undersea sights, Probert says, are "unparalleled." At Cocos Island, "you never know what you will see... very unspoiled above and below the water," he says. "Guaranteed to see things unlike other places in the world."

Avi Kalpfer, owner of island ferry Undersea Hunter, says that Cocos is a "paradise for divers."

"More fish than anyplace I know in the world, schools of fish and sharks, silkies, hammerheads," he says.

There are only three live-aboard boats that make the journey to Cocos, and only 60 divers are allowed on the island at a time. The government of Costa Rica prides itself on setting aside one quarter of its territory for national parks. The country is home to five percent of the world's total biodiversity.

Cocos Island's unique marine life is an important part of the Costa Rican national park system. It is one of the few places in the world where hammerhead sharks swim in observable schools.

"The incredible thing is that you have these beautiful, vicious animals that get right up close to you and get cleaned by these docile fish," says diver Peter Tattersfield. "It really makes for an adrenaline dive and keeps you coming back for more."

"Other places you see stingrays, but here they are huge," says diver Bill Greene. "And the hammerheads -- what a weird creature -- how could the Lord create such a creature? And you go home and you say to yourself, 'Wow. I've got to see that again and Cocos Island has it.'"

Because fishing has been outlawed within five miles (eight kilometers) of the island, more than 200 species of fish find protection in the reef system, creating a diver's paradise.

Here you can find huge schools of tuna, and jacks so thick in numbers they can dwarf a diver. Six of the eight known sea turtle species make their home here, and schools of marble and spotted eagle rays are so friendly they sometimes come right up to divers to check them out.

"This is my fourth trip out here with spectacular views, great fish, a beautiful place," says diver Larry Serafin. "I like unspoiled places that are environmentally protected, away from civilization to see nature as it is."

Cocos Island is certainly a place to do that -- again and again.