A "gate to hell" in Turkey has been discovered by Italian archeologists while excavating the ruins of a temple in Pamukkale, in the southwestern province of Denizli.

Archeologists explained that the gate, known as Pluto's Gate as the portal to the underworld in Greco-Roman mythology and tradition.

Greek geographer Strabo explained about the cave opening, "The space is full of a vapor 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."

The discovery was made by a team led by Francesco D'Andria, professor of classic archaeology at the University of Salento.

"We found the plutonium by reconstructing the route of a thermal spring -- indeed, Pamukkale's springs, which produce the famous white travertine terraces, originate from this cave," D'Andria told Discovery News.

"People could watch the sacred rites from these steps, but they could not get to the area near the opening. Only the priests could stand in front of the portal," D'Andria said.

"We could see the cave's lethal properties during the excavation," he says. "Several birds died as they tried to get close to the warm opening, instantly killed by the carbon dioxide fumes."