One wall, have a big map mural. Ben's room. And add details like - where Spiderman hangs out (NY) and find Gotham City. Where the Snow Leopard is that we adopted, places we have been on holiday etc.
NYC SUBWAY MAP!! This New NYC Subway Map May Be the Clearest One Yet
1990 atlas to the DC Heroes roleplaying game
Try really hard not to look at the answers before you come up with your own, as tempting as it is.
A COLLECTION OF BAT-LABELS — GIANT LIGHTED LUCITE MAP OF GOTHAM CITY
Idea -- things like this to decorate Hope's "office"/guest room Beautiful vintage tourist map of Gotham City
http://www.robertsonwade.com/projects/worldvision/ World Vision Child Health Now report design
Gotham City Map (from the Nolan trilogy)
Gotham City Batman Inspired Map of Gotham City Custom Raised