Layer of Carceri
The fourth layer of Carceri is a realm of mountains so tall, rough, and cruel as to stagger the imagination of a traveler from the Material Plane. Travel on foot here is almost impossible, because the land is divided by canyons miles deep where it is not lifted to absurd heights by mighty tectonics. A few trading routes do exist, usually in the form of rickety bridges and cliff-face trails barely wide enough for one. It's impossible to move normally away from the areas along the trading routes. Characters must make Climb checks (DC 15) to move one-half their speed as a miscellaneous full-round action.
Garden of Malice: The hanging gardens of Colothys are found on a single orb of the layer that travelers would do well to avoid. To the inexperienced eye, many of the cliff faces and sheer slopes of this orb are home to thick vines and tubers that sprout a riot of beautiful flowers. Characters who attempt to collect samples for their botanical collections quickly learn that the vines are animate and determined to wring the life from any creature that would dare to use them as climbing aids, defoliate the flowers, or even move too close. It may be that the animate vines represent one large organism that has grown through the eons to cover one whole orb. Once every six hundred days, the vines release tiny seeds into the air that look like dandelion fluff. The winds of the layer often send the seeds blowing across several hundred other orbs of the mountainous realm. Though many are eaten by vermin, many other seeds have also found nourishing soil, and have sprouted tubers in small nooks and forgotten cliff-faces on other orbs.