A Cold Tunnel                                          -      N      - 
(-------------------------------------------------)     - <---(M)---> -
                                                        -      -     SE

This is a cold tunnel beneath a brick house.  The walls are chilly to the
touch, and the ground is very hard.  The ceiling was cut low, but there is
room for five people to walk down the hall without bumping in to each other.
The tunnel was made unmistakably cleanly, and the walls are very flat,
almost as if some arcane magic had caused this.  To the north and to the
southeast is more of the tunnel.