The Edge of A Large Pit                                -      N      - 
(-------------------------------------------------)     W <---(M)---> E
                                                        -      S      -

You are walking through a huge chamber somewhere beneath the surface of
the world.  There is a large pit to the south, and at the bottom you can see
a tunnel leading even deeper into the ground.  The edges of the pit are very
steep, but the floor below is slightly higher here than at other points. 
You might conceivably be able to drop down from here, but it looks rather
dangerous and you might want to look for a better route instead.