I had to cross a river to get to the entrance and I ran through the entire place and came out of top of a mountain with a waterfall. Looked like someone's hidden getaway up there, it was nice and tranquil.
I believe it's Sorcerer's dungeon?
There's a room down there somewhere which has a magic crystal in it, if you double click that, it teleports you to a hidden room where a mummy and a lich lord spawn.