The magnificent old city of Ghent was one of the biggest cities in Western Europe at the end of the Middle Ages, renowned for its textile industry. Today it is the third biggest city of Belgium and one of the most beautiful ones. Much of the city's medieval architecture remains intact and is remarkably well preserved. Interesting highlights are the Saint Bavo Cathedral with the Ghent Altarpiece, the belfry, the Gravensteen castle, and the splendid architecture along the old Graslei harbor. The city of Ghent also houses three béguinages, recognized by UNESCO as World Heritage Sites, and numerous churches, among which the Saint-Jacobs church and the Saint-Nicolas Church are the most beautiful examples.