Chicago landmarks
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       Marker letters key the /atlas.txt grid.
       
 (TXT) W  Willis Tower (skyline)
 (TXT) B  Cloud Gate (The Bean) (park)
 (TXT) A  Art Institute (museum)
 (TXT) K  Buckingham Fountain (park)
 (TXT) N  Navy Pier (landmark)
 (TXT) S  Soldier Field (sport)
 (TXT) F  Field Museum (museum)
 (TXT) M  McCormick Place (landmark)
 (TXT) U  United Center (sport)
 (TXT) R  Wrigley Field (sport)
 (TXT) G  Guaranteed Rate Field (sport)
 (TXT) L  Lincoln Park Zoo (park)
 (TXT) D  Midway (MDW) (transit_hub)
 (TXT) O  O'Hare (ORD) (transit_hub)