This is the third in a series of cutaway cubes (I like to call them "cube slices", even though that's probably a contradictio in terminis...), following a pleasant town scene at dusk (Vystrigg Harbour) and a square section of a regional map (the Straits of Qalimbâr).
This time I mapped part of an underground structure called the Aswari Atrium, the place where several underground tunnels (some dry, some only navigable by boat) come together. There's a smattering of fun and weird labels to lighten things up, along with some mysterious structures that are left to the viewer's/player's imagination. Such as a vertical, partly submerged shaft called the Fathomless Deep and a few corridors leading off to the sides where other structures might lay. Or maybe just ruins. Or dead ends. Or cracks leading to the Underdepths or whatever. Just go wild with it!