Hmmm. I did a little search and found alot of stuff on sister cities. However, (and I'm sure you all have discussed this sometime back) Philly's twin towers Liberty One and Liberty Two. but they're mentioning Land of Two Cities and the mirror stuff so I don't know. I was thinking of Paris and London though.
Does anyone still have the link to those photos of towers in the various cities? I do believe Liberty (in Philly) was included on the list.