overall map                                    
                                               
             slums area                                     
            /   |   |     \                     
           /    |   |      \                    
           u --|-------|
           r   |citadel|-- residential                    
           b --|-------|     a       
          /a       |         r              
         / n       |         e                  
        /      urban area -- a                               
     sewers       |                            
                  |                            
                plains                         
                  |                            
                  |                            
                forest--mountains         
                    |      |                   
                    |      |                   
                  glen -- caves                
                             |                 
                             |                 
                            coast