[2023] Suggestion for the world-building team.

I would love to see an above-ground river abruptly fall into a hole in the ground to the underrealm, and after the waterfall just continue down there as one of the those underrealm rivers Steven mentioned. Essentially making it a one-way trip into that part of the underrealm, with some potential falling damage on the way. Maybe even make a plateau-like area down there, and then another waterfall, so the only way to get to the plateau is from the top. Also please add some neato underrealm fishes we can catch.

Being a professional artist, I made some reference art to illustrate what I mean. You can freely use it ingame: