Inside Costa Rica’s ‘cave of death’ which kills all that enters

Take a deep breath before trekking here.

Deep in the volcanic mountains of Costa Rica hides a deadly, yet small opening of the Earth that engulfs and kills just about all that enters.

Locals in the Alajuela Province call this six-foot-deep and ten-foot-long hell hole — accompanied by warning signs of skulls and crossbones — the Cueva De La Muerte, or the cave of death in English.

How can such a cramped space be a ruthless killer?

Not from any beast or poisonous plants, snakes, or spiders, but instead by toxic air — something researchers in 2022 warned of in caves across the world.

“This is a very small cave, but it’s unusual in that there’s a substantial seep of carbon dioxide gas coming,” explorer Guy van Rentergem said in a YouTube video at the site, measuring 30 kilograms of that CO2 being emitted per hour.

Not even the blob wouldn’t stand a chance under those conditions. One traveler photographed a bird that died in the small space.

“The CO2 layer is essentially unreadable by small animals, or even humans for that matter. So small animals enter the cave and asphyxiate, usually within a few moments.”

Located near the Poas Volcano and on the campus of the Recreo Verde Hotel and Spa, guides will carefully approach the cave’s lethal abilities and do demonstrations with fire torches.

The lack of oxygen extinguishes the blaze in a split second.

Adding to the terror, it is especially deceiving because oxygen is present at the small enclave’s top layer — but close to the ground is where no creature can properly breathe and would perish.

The dense amounts of carbon dioxide surface due to an unusual alignment from the San Miguel geological fault, according to the hotel.