Boulogne-sur-Mer is one of France's main fishing towns and naturally places a heavy emphasis on all things connected with the sea. Quieter and more atmospheric than nearby Calais, it's a lovely place for a day trip or a short break taking in the town and the surrounding Opal Coast, which includes the headland of Cap Gris Nez, the closest point in France to England, and the battlefields of Crécy and Agincourt, inland.
The fish market on the Quai Gambetta is a good starting point for visitors. From there, a hill leads towards the old town, with shops and restaurants along the way, and quiet cobbled streets within its medieval walls - a circuit around which takes about 45 minutes. At the top of the hill is the domed Cathedral, in the crypt of which are stone cannon balls used by Henry VIII's army when he besieged Boulogne. Also in this part of town is another sea-themed attraction, the Nausicaa aquarium, which showcases marine life from around the world, including sharks, jellyfish, sea lions and penguins.