Swamps and jungles are very similar when discussing their use in a role playing game (and we are). Both speak to the trackless wilderness and the potential for lost or degenerate civilizations, sometimes both. Both are oppressive environments, run riot with plants. Additionally, they’re each home to some ferocious and some weird monsters.
Now where they differ is in mood. Jungles are tense because of the threat of nature triumphant. Swamps are tense because of the threat of decay triumphant. While in a jungle you expect savage tribes and the ruins of lost civilizations, in swamps you expect the degenerate remains of ancient civilizations and things best forgotten, and that’s creepy.
What I expect in a jungle looks a lot like Iskandria – abandoned temples full of gold, lost cities (possibly still inhabited), hostile tribes of monkey-goblins, maybe even dinosaurs, and enough heat and humidity enough to slow broil the PCs in their armor. The dominant colors are green, dark green, and emerald green with bright highlights of crimson. Jungles should be overflowing with life, much of it hostile or hostile if cornered. There will be streams, waterfalls, and clear pools of water.
Swamps should be oppressive for their silence, broken only by occasional the eerie calls of monsters and animals. In swamps, the ground itself should be hostile with quicksand, bogs, and hummocks being common. Water should dominate, water brown with tannic acids leached from plant debris that has fallen into it. Leeches should be a serious concern, along with alligators and carnivorous fish. Frog-men and degenerate demi-humans will be found living deep in the swamp, either the remains of cursed civilizations or worshippers of dark, forgotten deities. The humidity should be a wet heavy blanket that is always pressing down on the PCs. The possibility of the undead is always strong.
Now why would adventurers go into either of these two hostile environments? Several reasons. Both likely contain lost temples and any adventurer worth his salt knows that lost temples contain gold and magic items (the fact that there may be monstrous guardians as well usually slips their minds). There is also the possibility of lost expeditions to rescue (or verify their death), kidnapped locals, and, especially in swamps, foul cults to put down.
I’ve put both types of terrain on my large scale map. Now I just need to add interesting places in these locations and then weave clues to their locations in places the PCs already know about.
Which brings up another topic I’ll discuss next week – the difference between travelling through the wilderness and actually exploring it.