Known in Sardinia as Casteddu, the island's capital has steep streets and impressive Italianate architecture, from modern to medieval. This city of nearly 160,000 people is characterized by a busy commercial center and waterfront with broad avenues and arched arcades, as well as by the typically narrow streets of the old hilltop citadel (called, simply, “Castello”). The Museo Archeologico makes a good starting point to a visit. The imposing Bastione di Saint Remy and Mercato di San Benedetto (one of the best fish markets in Italy) are both musts.