On the Dome of Atlantis                                -      -      - 
(-------------------------------------------------)     W <---(M)---> E
                                                        -      -      -

You are standing on the great Dome of Atlantis.  The dome stretches in
every direction from here.  Apparently, the Merfolk guard this dome very
securely, for there are guards up here, and they don't look friendly.  The
Dome is all that protects Atlantis from the crushing weight of the ocean
above, and the guards seem to understand the seriousness of their positions.
An Atlantis Dome guard is here, guarding his city from invaders.