Deciphering the Ancient Roman’s ‘Gateway to Hell’

A cave that the ancient Romans thought was the gate to hell, so deadly that it killed all animals that came near, but at the same time did not harm the priests who led them.
A cave that the ancient Romans thought was the gate to hell, so deadly that it killed all animals that came near, but at the same time did not harm the priests who led them.

Millennia later, scientists believe they have figured out why – a dense cloud of carbon dioxide causes animals that breathe it to suffocate. Dating back 2,200 years, the cave was rediscovered by archaeologists from the University of Salento in 2011. Simulation image of Plutonium It was located in a city called Hierapolis in ancient Phrygia, in what is now Turkey, and was used for animal sacrifices, which were bulls led through Plutonium, or the Gate of Pluto, the ancient god of the underworld – by the purified priests. The purified priests are sacrificing bulls As the priests led the bulls in, people could sit on high chairs above and watch the smoke billowing from the gate killing the animals. “ This space was so full of fog and dense that one could hardly see the ground. Any animal that goes inside is met with instant death. I threw the sparrows in and they immediately took their last breath and fell. ” wrote the Greek historian Strabo (64 BC – 24 AD). A photo showing dead birds at the entrance to “Hell’s Gate” It was this phenomenon that alerted the archaeological team to the location of the cave. Birds flying too close to the mouth of the cave suffocated and fell – indicating that, thousands of years later, it is still as deadly as ever. The culprit is seismic activity underground, according to volcanologist Hardy Pfanz of the University of Duisburg-Essen in Germany, who led a study of the cave’s gas in 2018. A fissure runs deep inside. below the area emitting a large amount of volcanic carbon dioxide. Today’s Status of Plutonium The team measured carbon dioxide levels in the area connected to the cave, and found that the gas – slightly heavier than air – forms a layer 40 centimeters (15.75 inches) above the floor. They found that the gas is scattered by the Sun during the day, but it is most dangerous at dawn after a night of accumulation. Concentrations that reach above 50% at the bottom of the lake, about 35% at 10 cm, can even kill a person – but, above 40 cm, concentrations drop rapidly. During the day, there was still some carbon dioxide about 5 centimeters high, as evidenced by dead bugs found by the team on the floor of the site. And inside the cave, they estimate CO2 concentrations consistently range from 86 to 91 percent, as neither the Sun nor the wind can enter. An inscription at the site indicates the hell gods Pluto and Kore. (Francesco D’Andria / University of Salento) The team notes in their paper that there is a strong touristic element to the place. Tourists could purchase small animals and birds that they could throw down for sacrifice, and on holidays larger animals were sacrificed by priests. “While the bull was standing in the lake with its mouth and nostrils 60 to 90 cm high, the large, mature priests (galli) always stood upright in the lake, ‘ the team wrote in their 2018 paper. Spectators will see large, strong bulls that can’t stand the smoke for a few minutes, while the priests remain strong and proud – a testament to the power of the gods and priests to perform. present to the people at that time. However, researchers believe that the priests were well aware of the characteristics of the cave and surrounding arena, and were able to conduct major sacrifices at dawn or dusk in the early days. Quiet day for maximum effect. Current status of the area They may also burrow their heads inside or into caves during midday ceremonies to demonstrate their abilities, holding their breath to endure. But the presence of oil lamps also suggests that priests approached the cave at night, according to the researcher who found it, Francesco D’Andria. Currently, the ancient city of Hierapolis still becomes one of the attractions attracting thousands of tourists.