The only true oceanic island off Central America, Isla Cocos—500 kilometers southwest of Costa Rica—is a 52-square-kilometer mountainous chunk of land that rises to 634 meters at Iglesias Peak. Declared a UNESCO World Heritage Site in 1997, the island is the northernmost and oldest of a chain of volcanoes, mostly submarine, stretching south along the Cocos Ridge to the equator, where several come to the surface as the Galápagos Islands.

These islands were formed by a hot spot, which pushes up volcanic material from beneath the earth’s crust. The hot spot deep inside the earth remains stationary while the sea floor moves over it. Over time, the volcanic cone is transported away from the hot spot and a new volcano arises in the same place.

Cliffs reach higher than 100 meters around almost the entire island and dramatic waterfalls cascade onto the beach.

Cocos’ forested hills supposedly harbor gold doubloons. More than 500 expeditions have sought in vain to find the Lima Booty—gold and silver ingots that mysteriously disappeared while en route to Spain under the care of Captain James Thompson.

The pirate William Davies supposedly hid his treasure here in 1684, as did Portuguese buccaneer Benito “Bloody Sword” Bonito in 1889. The government has placed a “virtual moratorium” on treasure hunts, although the Ministry of Natural Resources sanctioned a hunt in January 1992 by North American computer company owner John Hodges—for a rights fee of $100,000.

Cocos Island is inhabited only by national park guards who patrol the park equipped with small Zodiacs. The only safe anchorage for entry is at Chatham Bay, on the northeast corner, where scores of rocks are etched with the names and dates of ships dating back to the 17th century.

There are no native mammals. The surrounding waters, however, are home to four unique species of marine mollusks. The island has one butterfly and two lizard species to call its own. And three species of birds are endemic: the Cocos Island finch, Cocos Island cuckoo, and the Ridgeway or Cocos flycatcher.

Three species of boobies—red-footed, masked, and brown—live here, too. Cocos is also a popular spot for frigate birds to roost and mate. The white tern, which may hover above your head, is the espíritu santu, or Holy Spirit bird.

Feral pigs, introduced in the 18th century by passing sailors, today number about 5,000 and have caused substantial erosion.

Access to the island is restricted.

Friends of Cocos Island (FAICO, tel. 506/240-9383, www.cocosisland.org) works to protect the area from illegal fishing.