A dangerous, alien plane where glowing frog-slimes slither and slurp, metal-skinned bird people rebuff diplomacy, and only the endless subterranean tunnels are safe (just mind the gravity-bending moles). Visitors will have to skulk around in the dark to avoid the curse carried by the sunlight. Because (have I mentioned?) the sun is the source of a powerful curse--one that covers the whole planet.
The city was cursed many years ago. Since then it has not stopped raining. The gutters are inhabited by eels and the doors are on the first floor, coated with pitch. On a bad day, you can see the water level rise above the ground floor windows. Carts have both wheels and bladders filled with air to keep them afloat. And yet everyone is surprisingly dry.