The village is entered through the ancient and monumental Porta Nova and winds its long and narrow way in a sequence of fine 16th- and 17th-century noble houses (notable are Palazzo Usimbardi, Palazzo Buoninsegni and the Town Hall) to the Palazzo Campana, which marks the entry to the Castle, the oldest part of Colle. Here, the village is characterized by narrow paved lanes, 15th- and 16th-century noble houses (such as Palazzo Luci, Palazzo Morozzi, Palazzo Giusti, Palazzo Dini) and tower-houses, including the one where Arnolfo di Cambio was born.