The religious and political heart of Turin, this huge square was built as part of urban reorganisation work carried out by architect Ascani Vitozzi (1539-1615). The city's main streets lead off the square, which is bordered on one side by Palazzo Reale and the arcades of the Teatro Regio. Between Via Roma and Via Pietro Micca, note the controversial Torre Littoria (1932). In the centre of the square stands the imposing castle from which it takes its name (the castle was later named Palazzo Madama).