ToME: the Tales of Maj'Eyal

Hi,
I've found a couple of "hidden" areas. By this I mean rooms you have to tunnel to. The two I've found are:
- Empty room in you "home" above the butler room
- Room full of orcs and doors below where you get the Orb of many ways.

Just wondering what other ones there are?

There are a small number of vaults that have diggable areas containing monsters and/or treasure. The most common of these is the "thieves' house" that appears in forested zones.

There are some rectangular "monster nests" that are sealed in rock, which appear in the Infinite Dungeon, as well as Dreadfall, and I don't know where else. You might not even know these are here unless you've got some means of monster detection (Track, Preternatural Senses).