NOEL KING, HOST:
When Colombia's long guerrilla war ended, the country was able to open up new areas to tourism, including some areas that are not for people who spook easily. Gorgona is a snake-infested island that once housed a penal colony, and reporter John Otis went there.
JOHN OTIS, BYLINE: Gorgona National Park is located on an island 21 miles off Colombia's Pacific coast. Birds, lizards and monkeys are everywhere. So are snakes.
UNIDENTIFIED PERSON #1: (Non-English language spoken).
OTIS: These park rangers have just caught a Bothrops asper snake. It's tiny but deadly, says Mateo Lopez, a Colombian marine biologist doing research here.
MATEO LOPEZ: Bothrops - complicated one.
OTIS: It'll kill you?
LOPEZ: If you don't have the medicine here, you have 24 hours to reach a nice hospital, a good one.
UNIDENTIFIED PERSON #2: (Non-English language spoken).
UNIDENTIFIED PERSON #3: (Non-English language spoken).
OTIS: Spanish conquistador Francisco Pizarro learned about this hazard the hard way. When he landed here in 1527 on his way to conquering Peru, Pizarro lost so many men to snakebite that he named the island Gorgona. That's Spanish for Gorgon, the mythical female monster with venomous snakes in place of hair.
Gorgona was mostly uninhabited until 1960. That's when the Colombian government turned the island into a penal colony for 1,200 inmates. A British documentary film crew paid a visit in 1966.
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UNIDENTIFIED PERSON #4: There's no capital punishment for murder in Colombia. Instead, there's Gorgona Penitentiary.
OTIS: It turned out to be a disaster. Guards abused inmates. Several prisoners escaped on rafts. Meanwhile, 70% of the three-mile long island was deforested.
(SOUNDBITE OF TREE FALLING)
OTIS: The documentary shows chain gangs chopping down trees to build barracks and feed the wood-burning stoves in the prison kitchen.
In 1984, the government closed the penal colony and declared the island a national park. But Gorgona has struggled to attract tourists. It didn't help that Marxist guerrillas raided the island shortly before a 2016 peace treaty ended the war.
UNIDENTIFIED PERSON #5: (Non-English language spoken).
UNIDENTIFIED PERSON #6: (Non-English language spoken).
OTIS: But for adventure-seekers, there's a lot to love about Gorgona. Fishing is prohibited, so there are plenty of sharks and other marine life to enthrall scuba divers. It's also a prime spot for whale watching.
UNIDENTIFIED PERSON #7: Whoa.
UNIDENTIFIED PERSON #8: Oh.
OTIS: The calm waters of the sheltered side of the island attract humpback whales during mating season. In the course of an hour-long boat ride, we spot a half-dozen of them.
UNIDENTIFIED PERSON #9: Oh, wow.
OTIS: Back on the island, park rangers lead tours of the penal colony, or at least what remains of it.
UNIDENTIFIED PERSON #10: (Non-English language spoken).
OTIS: The jungle that was cut down by inmates has returned. Now vines crawl up the prison walls and rubber trees sprout from what was once the mess hall. Tourist Julia Berger is a kindergarten teacher from Germany.
JULIA BERGER: Yeah, it's impressive to see how the nature takes everything back, how you can see the trees and everything. So it's amazing (laughter).
OTIS: Just before the tour ends, our guide points out that the prison has at least one new occupant.
UNIDENTIFIED TOUR GUIDE: (Non-English language spoken).
OTIS: Slithering across the prison grounds is a six-foot-long boa constrictor. For NPR News, I'm John Otis in Gorgona National Park, Colombia. Transcript provided by NPR, Copyright NPR.