A cave ancient Romans believed was a gateway to the underworld has been discovered by scientists.
Rediscovered by archaeoligists from the Univeristy of Salento seven years ago, the cave – which dates back 2,200 years – was located in a city called Hierapolis in ancient Phrygia, now Turkey, and was used for animal sacrifices.
It was thought to be so deadly, it killed all animals which entered its proximity – though it never harmed the priests who led them there, apparently.
As they led bulls through the Plutonium – or Pluto’s Gate – people would watch on raised seats in an arena.
Greek historian Strabo (64 BCE – 24 CE) once wrote:
This space is full of vapour so misty and dense that one can scarcely see the ground. Any animal that passes inside meets instant death.
I threw in sparrows and they immediately breathed their last and fell.
Archaeologists who went to the cave’s location found birds flying too close to its entrance were still suffocating and dropping dead, proving the rumours to be true, report Science Alert.
So what’s to blame? Volcanologist Hardy Pfanz, of the University of Duisburg-Essen, Germany, put it down to seismic activity under the ground – a deep fissure below the region which emits large amounts of volcanic carbon dioxide.
Measurements taken of the carbon dioxide levels in the arena connected to the cave found the gas formed a ‘lake’ – 40 centimetres above the arena floor. Sunlight and wind helped disperse the deadly aroma.
Thus, entering the cave before dawn provides the deadliest level of concentration. It would ‘easily kill even a human being within a minute.’
Prof. Pfanz explained:
The Galli [Eunuch priests] stood on stones around the poor bull or goat and demonstrated their supernatural powers. At this height they could stand for 20-40 minutes without being endangered.
Nobody could enter the gate to hell without getting asphyxiated, but if the Galli kept their breath for a while, they could crawl into the gate up to their waist.