'Gate to Hell' is one of those blood-curdling places, which has been scaring the hell out of many for long. There are several places across the world, which have acquired a legendary reputation for being entrances to the underworld and are named as the 'Gates of Hell'.
An ancient Greek site, located in modern Turkey's western Denizli province is one of those horror-stricken places, which killed a few, who got closed to its gate. Legends of 'Hades Gate' is named after the Greek God of death.
Speculations had been rife that an angry God's breath is responsible for those deadliest happenings over the years, but the latest study led by a group of scientists from Germany's University of Duisburg-Essen threw cold waters to all those rumours.
The study, appeared in the journal of Archaeological and Anthropological Sciences shows that carbon dioxide gas coming from the Babadağ fault line is the reason behind those dramatic deaths at 'Hades Gate'.
"In a grotto below the temple of Pluto, CO2 was found to be at deadly concentrations of up to 91 percent," the study, led by professor Hardy Pfanz of the University of Duisberg-Essen, Germany revealed.
"Astonishingly, these vapours are still emitted in concentrations that nowadays kill insects, birds and mammals," the research added.
"Now to those who approach… anywhere around the enclosure the air is harmless, since the outside is free from that vapor in calm weather… but any animal that passes inside meets instant death," Greek geographer Strabo wrote.
Strabo witnessed a few animals who became victims of those noxious gas and vapour in the cave.
"At any rate, bulls that are led into it fall and are dragged out dead," he added.
However, this kind of places are generally located in regions of unusual geological activity, particularly volcanic areas, or sometimes at lakes, caves or mountains.
Legends from both ancient Greece and Rome record stories of mortals who entered or were abducted into the netherworld through such gates. Aeneas visited the underworld, entering through a cave at the edge of Lake Avernus on the Bay of Naples. Hercules entered the Underworld from this same spot.
This year-long rumour has made it a popular spot for millions. The ruins of Hierapolis, the place known as Pamukkale in modern Turkey is open for visitors to explore as well as the artifact-rich Hierapolis Archaeology Museum.
Moreover, the site, used as a healing spa since the second century B.C. under the Greek Seleucid Empire is also well-known for its bright turquoise pools and travellers can enjoy walking and taking baths in the therapeutic hot spring waters.