A vertical dungeon. Has anyone ever tried that?

[Kaptin Keen]

Well, you've got a better memory than me or most if you can keep an entire dungeon complex precisely memorized without drawing a map. That's great for you. I think most of us need a visual aid to remember where all the secret passages are, etc.

Having a map doesn't preclude someone from adding new passages and sections, nor improvising non-mapped areas. A map has no affect on your freedom to change things, it just keeps consistent what you've already created.

I didn't say I remember entire dungeons. I actually said the exact opposite: I have a general outline.

Let's use an example I never got to use: At the bottom of another dungeon entirely lies a series of caves - there are three, but obviously I can add another if I so desire - which contain the flooded remains of an underground settlement abandoned thousands of years ago.

An earth quake caused an underground river to be closed off, flooding the settlement up to second story hight - or depth, if you prefer. In other words, most of the buildings are now submerged, only larger ones being partially over water.

A race of aquatic creatures like ... water salamanders, say ... have moved in.

Now, I never got to use this. It has no point, there is no quest to solve here. But I still know, very precisely, what this is: Each of the caves a separate part of town - palace, cathedral, residence. I know the original use, and I know what the watermanders use it for.

Not an inch of it is mapped.

This was something I came up with years ago. Literally more than a decade back. It was made for Earthdawn, for chrissakes.

Now, you'd have me map it out. And for the life of me I cannot fathom what would be improved if I did.

The crux of the place is the fact that watermanders can move very quickly through water, and are effectively invisible below the surface (water is reflective, so ...) My intention was primarily a challenging fight, harassing them while they swam or rowed, and forcing a last stand on one of the buildings still above water. It's a thing I like to do - using opponents that are weaker than the players, but fight effectively in their own environment. Tuckers Kobolds-like.

And I can tell you the building they'd fight on. How it's partially defensible - but also has a stairway leading 'downstairs' which the watermanders can use to fall in their backs.

What do I need a map for?

Of course, the players might go for a different fight. But I fail to see how that's a problem - if they outsmart me, they will be rewarded.

Edit: Pointless bonus info - this dungeon was at the end of another vertical dungeon.