Erebus, the Sinking City

No one spoke. Ganymede fished his brain for a comment to break the awkward silence. He didn't want to say anything offensive, so instead he though to something positive.
“Good place for a swim.” He lied. The cliffs and sharp rocks and crashing waves actually made it less than ideal.
“This is a sea of death.” solemnly declared Umbriel.
“ H-horrible. I mean... horrible place for a swim.” he stammered.
-Tidal Lock

This is a drawing from my story Tidal Lock. It depicts Lady Umbriel, looking upon her city from a fare. The castle on the cliff is all the remains of the mostly sunken city. The ribbed ceiling can be seen, ceiling off the inhospitable environment outside. Water left mineral deposits have created a rugged landscape.