A ghat is a kind of quay or landing found along rivers in the East, particularly India. Unlike a Western pier, a ghat is a long set of steps that extend into the water, usually with a fortification-like buildings at their head. They're used for arrivals and departures for water travel and cargo, and as community gathering spots.
Imagine a long ghat flanking the underground river in your dungeon.
McKay Savage licensed the above photo under the Creative Commons.
(This is for the A-Z Blogger Challenge.)