Moscow, Constantinople (now Istanbul), and Rome itself are vitally alive in the present and are magnets for tourists. Also going back a long way, each lives in history. These cities have their points in common, each wanting to rule the world and establish Rome of the Caesars, Constantinople of the Emperors, and Moscow of the Tsars were also the Rome of St. Peter, the Constantinople of the Patriarchs, and the Moscow of the Orthodox Metropolitans...