ROME THEN AND NOW

Dating back to the beginning of the first millennium, some of Rome’s most famous architectural sites are among the most ancient in the world. They survive in an enchanting urban tableau of classicism and modern Italian culture. Here are all of Rome’s most famous tourist attractions — the Coliseum, St. Peter’s Square, the Trevi Fountain, the Spanish Steps — represented in dozens of photographs, old and new, that bring the great city to life.