In Pamukkale, western Turkey, a huge white rock formation rises above the surrounding plain.
The mountain falls in the form of petrified waterfalls to the bottom of the valley, filling it of stalactites and pools of sparkling turquoise water.
These rock formations are called travertines, limestone cliffs created slowly during 160, 00 0 years due to the bubbling of mineral springs.
In its formation process, the water degasses as it flows down the slope, leaving a large deposit of bright white calcium carbonate almost 3 kilometers long and 160 meters high.
This is not the only place on the planet where travertines are found. There are more in Huanglong, China, and Mammoth Hot Springs in Yellowstone National Park, USA.
But those in Pamukkale are the largest and possibly the most magnificent in the world. . They are one of the most popular tourist attractions in the country and are so spectacular that their name in Turkish means “cotton castle.”
Before the pandemic, more than 2.5 million people a year traveled to Pamukkale from Izmir or Istanbul, stepping off the tour buses atop the dazzling plateau and swarming the landscape like ants on a gigantic sugar mound before heading to the beaches of Bodrum or the historic ruins of Ephesus.
But visitors who simply dip their toes in the vivid mineral pools and take a selfie in front of the natural columns miss a detail. Because perched high on the white cliffs of Pamukkale is an even more fascinating attraction: the ruins of the beautiful ancient city of Hierapolis .
A city with a “chilling” spectacle
Hierapolis was founded by the Athalid kings of Pergamum at the end of the 2nd century BC. . Before being taken by the Romans in the year 133 d. C.
Under Roman rule, the place became a prosperous spa town. During the 3rd century, visitors from all over the Empire came to admire the scenery and bathe in the supposedly healing waters.
The city’s success is still visible at its impressive gate arched entrance, its colonnaded main street and its beautifully restored amphitheater , all built from the same local travertine stone that glows golden in the warm Turkish sun.
“The hot springs are probably one of the main reasons for the founding of the city,” says Dr. Sarah Yeomans, an archaeologist at the University of Southern California specialist in the Roman Empire. “In the middle of the second century, Hierapolis was a beautiful and bustling spa town with what I imagine was a dynamic and diverse population given the popularity of these places among visitors.”
But Hierapolis was also known throughout the Roman world for another more sinister reason. It was said to be the location of a “gate to hell,” a portal to the underworld where the toxic breath of the three-headed dog Cerberus flowed from the ground, claiming unsuspecting victims on behalf of its master, the god. Pluto .
The city included a sanctuary, the P Lutonian , to which the pilgrims came from different parts and paid the priests to make sacrifices in the name of Pluto.
The writers of the time, including Pliny the Elder and the Greek geographer Strabo , described these sacrifices as a chilling spectacle.
The priests brought animals to the sanctuary, such as sheep or bulls. By “the hand of the god”, the animal fell dead instantly while the priest came out alive.
“I threw sparrows, and immediately they gave their last breath and they fell ”, wrote Strabo in the Book 13 from his Geography encyclopedia, clearly in awe of what he had just witnessed.
If you visit Plutonion today, it is hard to imagine that those dramatic scenes were real.
Now excavated and restored, the sanctuary is a quiet place that includes a rectangular enclosure filled with crystal clear water and a small arched doorway on one side. At the top there are tiered seats for spectators and a replica of the statue of Pluto.
How could the priests survive while the animals died?
Carbon dioxide at “ultra high” levels
Hardy Pfanz, a biologist at the University of Duisburg-Essen in Germany who studies gases geogenic, he was intrigued.
“When I read the descriptions of the ancient writers, I began to wonder if there could be an explanation scientific, ”he says. “I was wondering, could this door to hell be a volcanic vent?”
Eager to test his theory, Pfanz traveled to Hierapolis in 2013. “We weren’t sure what we would find. It could have been made up, it could have been nothing, ”he laughed. “We certainly didn’t expect to get an answer that fast.”
But he got an answer, almost immediately. “We saw dozens of dead creatures around the entrance: mice, sparrows, blackbirds, many beetles, wasps and other insects. So, we knew immediately that the stories were true. ”
When Pfanz tested the air around the vent with a portable gas, discovered the reason: toxic levels of carbon dioxide. Normal air contains only 0. 04% CO2, but Pfanz was surprised to find that the concentration around the sanctuary reached a staggering 80%.
“S or a few minutes of exposure to the 12% carbon dioxide could kill you “, Pfanz explains,“ so the levels here are really deadly. ”
These ultra-high levels of carbon dioxide are caused by the same geological system that created the hot springs and spectacular travertine terraces in the area.
Hierapolis is built on the Pamukkale fault, an active tectonic fault of 35 km long c n cracks in the earth’s crust allow mineral-rich water and deadly gases to escape to the surface. One of them passes directly under the city center and enters Plutonion.
“It is almost certain that the choice of the location of the Plutonium was directly related to the seismic gas vents that exist here Yeomans said. “Since the underworld and the deities and myths associated with it were an important part of their religious spirit, it makes sense that they built temples and shrines in places that most evoked the world they believed was under their feet.”
But such proximity to the forces of nature had a price: several earthquakes devastated the city over the years 17 d. C., 60 d. C., and again in the seventeenth and fourteenth centuries.
Finally, Hierapolis was abandoned.
Myth or trick?
But Pfanz was still puzzled by one thing: if this area was so deadly, why didn’t the priests on Plutonium die as well?
He returned to Hierapolis the following year and this time he studied the gas concentrations at different times of the day.
“We noticed that during the day, when it’s hot and it’s sunny, the carbon dioxide dissipates quickly, ”he says. “But because carbon dioxide is heavier than air, at night, when it’s colder, it accumulates in the sand, creating a lethal lake of gas at ground level.”
His conclusion: the animals, with their noses pressed to the ground, quickly suffocated in this toxic cloud, but the taller priests breathed much lower levels of CO2 and were able to survive.
¿ Was this show a massive money-making trust trick, or did the priests really believe they were communicating with the gods?
“There is no doubt that Pl Utonium in Hierapolis was a great deal” , says Yeomans, “but it’s hard to be sure if the priests really understood what was going on. Some may have attributed its survival to the favor of the divine, while others may have regarded it as a natural, albeit enigmatic, phenomenon that could be observed and, at least to some extent, predicted. ”
Today Today, the temple of Plutonium is bricked up and a walkway has recently been built around it to give visitors the opportunity to see the site without getting too close to the source of the deadly gas.
But Even with these modern adornments, it is exciting to be able to follow in the footsteps of the Greek and Roman pilgrims and contemplate the place where mythology and reality meet; where the ancient gods approached and touched the lives of the people.
“When I first recognized that the legendary breath Cerberus is actually carbon dioxide, he was standing right in front of the arch, ”says Pfanz. “At that moment, I realized that we had solved this ancient mystery; it was a really great feeling. ”
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