0one Games* has a huge dungeon adventure locale called
The Dungeon Under the Mountain. While most regions of this megadungeon cost a few dollars to download, you can get a one room preview for free.
In this free sample, you'll find:
- One map tile with a 1 inch grid
- A description for the location, with D&D 3.5 stats
This is definitely worth downloading if you're running D&D 3.X or Pathfinder. If not, it can still be a source of inspiration, but the crunch (a significant portion) will be useless.
Check it out by clicking here.
*I really wish I knew how to do the strikethrough like they have in their logo.