Gorges

Just as on the surface, water can carve deep canyons and gorges in the Underdark. An Underdark gorge is nothing more than a cave that runs vertically instead of horizontally. Gorges often feature streams and therefore life and food, although the difficulty of the terrain makes a gorge less desirable as a residence than a living cave with less extreme topography.

Since gorges can run for many miles, they often serve as the highways of the Underdark. Travel along the floor of a gorge can be very difficult, but many Underdark races take steps to improve these natural roads for the use of their own merchants and hunters. Gorges also offer good opportunities to change depth and perhaps access another level quickly, through a little climbing.