Vast Underground Cavern                                -      N      - 
(-------------------------------------------------)     W <---(M)---> E
                                                        -      S      -

You are walking through one of the largest chambers you've ever seen.  It
is quite cold down here, and you decide that you must be below the level of
the ground now.  The sound of water washing on a shore can be heard faintly
to the east, and you presume that there is a subterranean lake in the area. 
Looking up, you notice that there are many stalactites hanging from the
ceiling, and since they don't look very stable it might be a good idea to
remain silent.