Flickering gas-lit lanterns announce this 19th-century opera hall, modeled after Milan’s La Scala. Gilded and gorgeous, Philly's most opulent performance hall is known as the "Grand Old Lady of Locust Street." (Her massive crystal chandelier is to die for. )  This is where you can catch a performance of the Pennsylvania Ballet or Opera Philadelphia. If your musical tastes run more modern, this is also the main theater where traveling Broadway musicals perform, as well as the occasional pop icon like Prince.