A city in the Underdark

At some point the small path along the cliff, that you have been walking so far, leads onto a much wider and well treaded one. This path is even laid with bricks, and has other, smaller paths converging on it.

If only you would've been stronger, trained more, been faster. These are the thoughts going through your head, as a large underground city comes into view.

It is built out of dimly glowing, blue stone, with large, spiralling towers. Kind of beautiful, you muse to yourself. Would look even better torched to the ground though. Maybe you can get your hands on some new weapons in there?

You see a hill in the middle of the city, with a long and wide stairway leading up to a gigantic castle on top. Or is that a temple? If it was a castle you could maybe raid the armory, in a temple not so much...

You also make out a large, round building, with a wide open space in the middle. You have only been to one a couple times, the first time you and your friends went to the big city with the Adventurers Guild, but you'd still recognize an arena among a thousand other structures...