Idea -- things like this to decorate Hope's "office"/guest room Beautiful vintage tourist map of Gotham City
Like Tintin's age, Wolverine's daily lager intake, and the number of birthmarks on Popeye's body, the exact location of Gotham City is one of those comic book mysteries we will likely never receive a firm answer to.
Gotham City Map (from the Nolan trilogy)
Try really hard not to look at the answers before you come up with your own, as tempting as it is.
Map of DC Comic's Gotham City Home of Batman and Arkham Asylum - Eliot R. Brown
Gotham City Map
Map of Gotham City
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.
Gotham City, as seen in the Nolan films
Left two images: Eliot R. Brown's map of Gotham City, as it appeared in comics circa 1999; right image: Brown's map appearing in a recent issue of Batman