Prester John, in his letter, was kind enough to point out some of the hottest destinations in his many kingdoms.
- A land without poison, venom, & frogs. “In one region grows no poisonous herd, nor does a querulous frog ever quack in it; no scorpion exists, nor does the serpent glide amongst the grass, not can any poisonous animals exist in it or injure anyone.”
- A Paradise of gems, with no evil spirits. “Among the heathen flows, through a certain province, the River Indus. Encircling Paradise, it spreads its arms in manifold windings through the entire province. Here are found the emeralds, sapphires, carbuncles, topazes, chrsolites, onyxes, beryls, sardius, and other costly stones. Here grows the plant Assidos which, when worn by anyone, protects him from the evil spirit, forcing it to state its business and name — consequently the foul spirits keep out of the way there.”
- Pepper fields. “In a certain land subject to us all kinds of pepper is gathered and is exchanged for corn and bread, leather and cloth.”
- The Fountain of youth and Pebbles of keen sight. “At the foot of Mount Olympus bubbles up a spring which changes its flavor hour by hour, night and day, and the spring is scarcely three days’ journey from Paradise, out of which Adam was driven. If anyone has tasted thrice of the fountain, from that day he will feel no fatigue, but will, as long as he lives, be as a man of thirty years. Here are found the small stones called Nudiosi which, if borne about the body, prevent the sight from waxing feeble and restore it where it is lost. The more the stone is looked at, the keener becomes the sight.”
- The sea of sand and tasty fishes.“In our territory is a certain waterless sea consisting of tumbling billows of sand never at rest. None have crossed this sea — it lacks water all together, yet fish of various kinds are cast up upon the beach, very tasty, and the like are nowhere else to be seen.”
- The river of rolling stones. (Closed Friday-Monday) “Three days’ journey from this sea are mountains from which rolls down a stony, waterless river which opens into the sandy sea. As soon as the stream reaches the sea, its stones vanish in it and are never seen again. As long as the river is in motion, it cannot be crossed; only four days a week is it possible to traverse it.”
- The lands of lost tribes of Israel. “Beyond this stony river there are ten tribes of the Jews. Though they presume they are kings, yet they are subject to us, and are tributaries to our majesty.”
- The pool of healing (Closed to non-Christians) “In a certain plain, is a fountain of singular virtue which purges Christians and would-be Christians from all transgressions. The water stands four inches high in a hollow stone shaped like a mussel-shell. Two saintly old men watch by it and ask the comers whether they are Christians or are about to become Christians, then whether they desire healing with all their hearts. If they have answered well, they are bidden to lay aside their clothes and to step into the mussel. If what they said be true, then the water begins to rise and gush over their heads. Thrice does the water thus lift itself, and everyone who has entered the mussel leaves it cured of every complaint.”
- An underground stream, filled with gems.“A subterranean rill which can only by chance be reached, for only occasionally the earth gapes, and he who would descend must do it with precipitation, ere the earth closes again. All that is gathered under the ground there is gem and precious stone.”
- Zone, a land with fire-salamanders. “These worms can only live in fire, and they build cocoons like silk-worms which are unwound by the ladies of our palace and spun into cloth and dresses which are worn by our Exaltedness. These dresses, in order to be cleaned and washed, are cast into flames.”
- The mirror of all-seeing. “Before our palace stands a mirror, the ascent to which consists of five and twenty steps of porphyry and serpentine … This mirror is guarded day and night by three thousand men. We look therein and behold all that is taking place in every province and region subject to our scepter.”
- Towers of true-seeing. “Now the columns and bases are of the same kind of precious stone as the steps through which men ascend. On the summit of the highest there is a watch-tower placed by some graceful skill, so that no one in the various kinds of laud subject to us can work any fraud, or treachery, or dissensions against us whatever, nor those among us, without it being clearly seen from that watch-tower, and without its being recognized who they are, or what they do. There are three thousand men of arms ever guarding this watch-tower night and day, lest by chance it be broken or overthrown to the ground.”
The last item is mentioned in a slightly longer but more archaicly phrased text here.
Gygaxian/adversarial DMs may want to take assume the all regions not noted for lacking poisonous creatures and evil spirits are infested with them.