Underground River                                      -      N      - 
(-------------------------------------------------)     W <---(M)---> -
                                                        -      S      -

As you flounder through this river, the deafening sound of water crashing
on the cave walls threatens to drive you mad.  The water is freezing cold,
and you wonder if you will manage to survive the frostbite sinking deep into
your limbs.  You flail your arms fighting desperately to keep your head
above the murky waters.