0X.07: Helgate Chasm
Form: A wide chasm lit by an ominous orange glow.
Illumination: Darkness except within a few dozen yards of the chasm, which is lit by a dim and malevolent orange light.
At First Glance: The tunnel from 0X.01 narrows and goes for a hundred yards or more before wideninging slighting into a cavern dominated by a rift in the earth. A chasm 50 feet wide blocks the cavern. It glows with light that might come from hell itself: red orange and ominous, stinking of sulfur, and carrying moans on its foul breeze.
On Closer Inspection: There is a definite updraft from the chasm as hot air rises. While there is no visible smoke on that breeze, it is foul with toxic gas. Anyone flying or hovering over the chasm for more than a few minutes may succumb to the gas, losing consciousness and tumbling in to their doom.
Secrets: Despite appearances, the chasm is not unpassable. There is a bridge built over the chasm, made of deepearth blacksteel constructed by the Baelishite dwarves who abandoned their bastion in 01.05. The bridge is invisible to those without deep sight (like dwarves) but can be discovered through trial and error.
Connections: Across the chasm, the tunnel continues west to 0X.xx and branches southwest to 0X/xx.