or Paleapolis (in the area east of Porta Nuova) and the Neapolis. Via Vittorio Emanuele was the main road east–west through this early walled city. The eastern edge of the walled city was on Via Roma and the ancient port in the vicinity of Piazza Marina. The wall circuit was approximately Porto Nuovo, Corso Alberti, Piazza Peranni, Via Isodoro, Via Candela, Via Venezia, Via Roma, Piazza Paninni, Via Biscottari, Via Del Bastione, Palazzo dei Normanni and back to Porto Nuovo. The walls followed the course of the two rivers that surround the city, the Kemonia and the Papireto , creating a natural moat and improving the military security of the city. During the Roman era , they were certainly implemented, as deducible from the subsequent account of Procopius of Caesarea about the capture of Palermo [1] , In the medieval period the city was expanded with a second wall. Via Vittorio Emanuele continued to be the main road east–west through the walled city. The west gate was still Porta Nuova, the walls continued to Corso Alberti, to Piazza Vittorio Emanuele Orlando where it turned east along Via Volturno to Piazza Verdi and along the line of Via Cavour. At this northeast corner the Castello a Mare protected the port at La Cala. A huge chain was used to block La Cala with the other end at Santa Maria della Catena (St Mary of the Chain). The sea-side wall was along the western side of Foro Italico Umberto. The wall turns west along the northern side of Via Abramo Lincoln, continues along Corso Tukory. The wall turns north approximately on Via Benedetto, to Palazzo dei Normanni and back to Porta Nuova. Several gates in the city wall survive. Opera houses Up until the beginning of 20th century there were hundreds of small opera theatres known as magazzeni in the city of Palermo. The Teatro Massimo ("Greatest Theatre") was opened in 1897. It is the biggest in Italy (), and one of the largest of Europe (the third after the Paris Opera and the Vienna State Opera), renowned for its perfect acoustics. Enrico Caruso sang in a performance of La Gioconda during the opening season, returning for Rigoletto at the very end of his career. Closed for renovation from 1974 until 1997, it is now restored and has an active schedule. The Teatro Politeama was built between 1867 and 1874. Other sights