[Ezekiel]

"This 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," the Greek geographer Strabo (64-63 B.C. to about 24 A.D.) wrote about the site.

"I threw in sparrows and they immediately breathed their last and fell," he added.

I'll take "Early White Hut Tours" for $1000, Alex.

[HiTech RedNeck]

This sounds like natural methane emissions concentrated to the point of asphyxiation. Birds would be quite sensitive to that in particular.

Nobody thought of tossing a burning object inside? (Hold my ancient ale and watch this!)

[SunkenCiv]

Thanks all for the pings!