In the heart of the Adda Sud Park and along the Serio Morto valley, we encounter the ancient village of Pizzighettone, one of the most beautiful walled towns in Lombardy. The Adda river cuts it in two and is a fundamental element of its identity. But the symbol of Pizzighettone is its 16th-century walls that completely surround the historic centre, on both banks of the river. Then there are the Casematte, rooms inside the walls, all interconnected: they are unique in Europe and definitely worth a visit. Also worth seeing are the Parish Church of S. Bassiano, the Civic Museum, which ranges from Prehistory to the Modern Age, and the Guado tower, the only intact testimony of the ancient castle. All around, the green landscape of the plain, to be discovered perhaps by bicycle or with a relaxing cruise on the Adda.