The Chicago Loop is the downtown area that is circumnavigated by the elevated train (known as the el), although mostly we say "in the Loop" to indicate anything located downtown, whether or not the el has a stop nearby. Does your city's downtown have a nickname?
p.s. This was a rainy morning about three weeks ago--it is actually bright and sunny right now. Thanks to all who visited while I was ghost blogging from another city--I'm back and will return to haunting my own city once again. Cheers, everyone!