The site on which Castelgrande stands is rich in history and archaeological findings unearthed during excavations in 1984-85 confirm that the site was inhabited as far back as the Neolithic period (5500-5000 B.C.) and though to Roman times. Excavation in 1967 brought to light evidence of the first fortification which dates from the 4th c.A.C. Documents dating from the 6th c. also mention the existence of this first defensive construction. The castle as we see it today was built in various stages and has undergone several restorations. Construction of the castle began in the 13th c.; it was enlarged in 1473-86 and later restored in the 17th and 19th centuries. The White and Black Tower date from the 13th and 14th centuries and are 27 and 28 meters high. Architect Mr. Aurelio Galfetti carried out the latest extensive restorations in 1984-91. The transformation is exemplified stunningly in the inner courtyard, the entrances, the elevator and the steps leading down to the town centre. The battlements are divided into three sections, one of which still descends right into the town centre. At the time of the Visconti, this remaining bulwark reached down as far as the river Ticino. It was built in the late 14th c. and fortified by the Sforza dukes of Milan between 1486 and 1489. In 1515, parts of the wall were destroyed by a flood ("Buzza di Biasca"). The castle stands 50 meters above the town and can be reached on foot in a matter of minutes taking the steep foot paths which climb up from Piazza Collegiata and Piazza Nosetto, or the gently winding road leading up from Via Orico which skirts the San Michele hill. Alternatively, there is a modern lift with access from Piazzetta Della Valle. Castelgrande is open all year.