Milan was a city in the former nation-state of Italy on Earth. The Teatro alla Scala, Earth's most famous opera house, was located here. (VOY: "Virtuoso") In 19th century San Francisco, a gentleman named "Mr. Pickerd" told his landlady Carmichael that he and his theater troupe had played to full houses in London, Paris and Milan. (TNG: "Time's Arrow, Part II" )