River Entrance at City Wall                            -      -     NE 
(-------------------------------------------------)     - <---(M)---> -
                                                        -      -      -

From a huge, roughly-hewn hole at the base of the wall, the river flows
into the city.  Across the hole, bars made of thick steel are spaced every
few feet, allowing only the creatures that belong in the stream to flow past
it.  Through the bars you can see an inviting forest and a large waterfall
in the distance.  
A small colorful fish darts between your feet.