From the entrance, it looks almost like a normal cave, with a rocky ledge and leaves scattered around the entrance.
The only thing that indicates it is a warning sign adorned with skulls and crossbones that says: ‘Danger! Not go beyond this point.’
This is Costa Rica’s Cave of Death, or ‘Cave of Death’ in local Spanish, located in the Recreo Verde resort complex in the Venice district.
Measuring 6.5 feet deep and nearly 10 feet long (2 meters by 3 meters), it instantly kills any creature that enters it.
However, this does not deter brave explorers from visiting the site in search of social media videos.
Visitors to the Cave of Death demonstrate its power by holding a lit torch at the entrance. Note the warning sign adorned with skulls and crossbones that reads: ‘Danger! Not go beyond this point’
La Cueva de la Muerte – or ‘Cave of Death’ in local Spanish – is located in the Recreo Verde resort in the Venice district, Costa Rica
According to Belgium-based cave explorer Guy van Rentergem, who visited the site several years ago, it contains a substantial amount of carbon dioxide (CO2).
In fact, the gas levels inside the cave are so high that they can cause loss of consciousness almost instantly, followed by the cessation of breathing.
Fortunately, humans are generally safe because it is too small to fit in and the signs in place are warning enough.
However, snakes, birds, rodents, and other small creatures quickly die after unintentionally entering the entrance, perhaps in search of food.
“This is a very small cave, but it is unusual because there is a substantial leak of carbon dioxide coming from the furthest slot at the back of the cave,” van Rentergem said.
In a clip posted on YouTube, Belgium-based cave explorer Guy van Rentergem (pictured) explains why the cave is so dangerous.
“Small animals will enter the cave and suffocate, usually within moments.”
About 30 kilos of carbon dioxide are emitted into the atmosphere every hour, which is equivalent to an average distance of 256 kilometers by car, the expert added.
“In one year, these 263 tons of carbon dioxide or the equivalent of a car traveling 2.2 million kilometers or 56 times around the world.”
It is unclear exactly what the source of the gas is, although van Rentergem says it is of volcanic origin.
During his visit to the Cave of Death, one of van Rentergem’s team members demonstrates the power of the cave by holding a lit torch at the entrance.
After a few seconds, the flame goes out, and that’s because the CO2 displaces the oxygen around the fire and makes it burn.
Because CO2 is heavier than air, gas concentrations are highest near the base of the cave, an additional danger factor for small animals.
TO study 2022 The Italian researchers noted that natural caves are particularly prone to “dangerous CO2 accumulations.”
This is because they encourage the release of “geogenic” CO2 into the atmosphere, that is, CO2 that comes from the Earth’s geological processes.
“Atmospheric CO2 concentrations can reach high levels within natural caves, posing a dangerous condition for both humans who frequent the underground environment,” the study authors stated.
The toxicity of CO2 at high concentrations is generally not well understood, meaning people who visit these types of caves may underestimate the dangers.
Other caves with high levels of gas include Movile Cave in Romania and Carburangeli Cave in Italy.
Peak Cavern in Derbyshire famously was the site of a tragic accident involving British student Neil Moss in 1959.
The 20-year-old Oxford University student lost consciousness due to inhaling CO2, although it was thought to be due to his own breathing pooling at the base of the cave shaft.
