For anyone in search of the spectacular, Carpi is known only for its square: Piazza Martiri.

On the one side of this huge open space, the Castello dei Pio is a symbol of power, combining buildings of different periods and towers of various girths in a compact structure. On the other side, the Portico Lungo arcade is an eloquent example of an architectural feature typical of the Po Plain. They both demonstrate the effects that can be achieved using just the humblest local material: brick - both the castle, with its uneven jumble of skyward projections, and the complex of buildings fronted by the Portico Lungo, are in unplastered brick.