Guides hand out knee-high rubber boots before leading visitors on hikes around Gorgona National Park, an island 21 miles off Colombia's Pacific coast. The boots provide traction in the mud — and protection from poisonous snakes.
The presence of scary reptiles is just one reason why the park remains largely unexplored by outsiders. It doesn't help that it is better known for its days as a kind of Colombian Devil's Island, when it housed a penal colony for 1,200 hardened criminals, from the 1960s-80s. Also, when tourism started to take off in Colombia a few years ago, Marxist guerrillas raided the island.
"Tourism on Gorgona has always been a challenge," Julia Miranda, director of Colombia's national park system, told NPR.
But for adventure-seekers there's a lot to love about Gorgona. Fishing is prohibited so there are plenty of sharks, rays and other marine life to enthrall scuba divers. It's a prime spot for whale watching. And the island is full of monkeys, lizards and birds, some of them endemic.
"It's like a mini-Galápagos," says Jorge Ramírez, manager of Gorgona's only resort, referring to the Pacific islands off Ecuador where Charles Darwin devised his theory of evolution.
Once home to Indigenous groups, the Colombian island got its name from Spanish conquistador Francisco Pizarro, who landed here in 1527 on his way to invading Peru. Pizarro lost so many men to snake bite that he named the island Gorgona. That's Spanish for Gorgon, the mythical female monster with a head full of venomous snakes rather than hair.
Gorgona remained mostly uninhabited until 1960. By then island-based penal colonies, such as Coiba in Panama, San Lucas in Costa Rica and Islas Marías in Mexico, were in vogue. So the Colombian government opted to turn Gorgona into a penitentiary for the country's most dangerous prisoners.
Surrounded by shark-infested waters, the prison was supposed to be escape-proof. However, several inmates, who were part of work crews cutting timber outside the prison walls, fashioned rafts out of balsa wood and managed to get away, said Corazón de Jesús Aguiño, a park ranger who oversees a small museum of the penal colony.
"It would take about 24 hours," Aguiño said. "The prisoners needed to wait for southerly winds because the shortest distance to the mainland is to the south."
The most infamous escapee was Daniel Camargo, a serial rapist and killer who spent three days on a makeshift canoe before reaching the Ecuadorian coast in 1984. He was later arrested and killed by a fellow inmate in an Ecuadorian prison.
By the early 1980s, Colombia's penal colony experiment was considered a disaster.
Guards were accused of abusing inmates. Prison work gangs chopped down most of the trees to make barracks and docks and to feed the wood-burning stoves in the prison kitchen that blazed 24 hours per day. The deforestation led to erosion and runoff that damaged nearby coral reefs, said Mateo López, a Colombian marine biologist doing research on Gorgona.
Under pressure from scientists and human rights activists, the Colombian government closed the penal colony in 1984 and declared Gorgona a national park. That provides some environmental protection. But its remote location and rustic accommodations — the tourist cabins once housed prison officials — turned off some travelers. What's more, the sea lanes around Gorgona are used by drug smugglers to ship Colombian cocaine. In 2014, drug-trafficking rebels attacked the island and killed a police agent.
"The area has always been a challenge for security and security is the No. 1 issue for tourists," said Miranda, the parks director.
However, the guerrillas agreed to demobilize under a 2016 peace treaty. Gorgona's jungle has grown back while the coral reefs have recovered and have become a major attraction for scuba divers. What's more, the sheltered side of the island is a favorite spot for humpback whales during mating seasons.
"This is the perfect environment for whales," said López, the marine biologist. "The acoustics between here and the mainland are very good for males to do their mating calls. The island acts as a barrier from heavy waves so it is very calm for the females to give birth."
During a recent visit, most of the tourist cabins were occupied and several visitors expressed fascination with how Gorgona had recovered.
"On the one hand it is horrible to see what happened to this island," said Julie Berger, 24, a kindergarten teacher from Germany. "But it is also impressive to see how nature takes everything back."
That includes the penal colony. These days vines crawl up its walls while rubber trees spring from the mess hall floor. And instead of human inmates, tourists on a recent visit spotted some slimy new occupants: two 6-foot-long boa constrictors.