|Hierapolis-Pamukkale was founded at the end of the second century B.C. Its thermal springs were thought to have great healing powers.
Ceded to Rome in 133 B.C., Hierapolis flourished, reaching its peak in the second and third centuries A.D. The gate was thought to belch the “breath of death,” killing all except the divinely immune priests who led animals to sacrifice. Scientists have provided an explanation for the mystery. Fissures in the earth’s surface beneath the site emits carbon dioxide at concentrations so high it may become deadly.|