En route between Dunkerque and Lille, the flat plain of French Flanders is punctuated by two very pretty towns worth pausing in, Bergues and Cassel. Bergues sits snugly behind its powerful brick fortifications, a town of neat lanes and a network of canals also part of Vauban’s defence system. In the town centre, there is a fine belfry, and the Musée du Mont-de-Piete de Bergues (www.bergues.biz/musee) which contains Georges de la Tour’s lovely Joueur de Vieille.

On an isolated knoll rising from the farmland (Mont Cassel, 174 m), perches Cassel, a delightful place of narrow streets and steps and a cobbled place lined with fine buildings, including the Hôtel de la Noble Cour, now the local museum.