Just before 8am on 4 August 1914, German troops started to pound across the border towards the small town of Visé, about 20km north-east of Liège. The residents of Visé had blockaded the road with trees, rocks and cars and then destroyed the town's bridge over the River Meuse.
Their efforts delayed the troops sufficiently to allow time for the Belgian army to arrive on the left bank of the Meuse. A three-hour battle ensued before the enormously outnumbered Belgian soldiers were forced to withdraw. It was the first confrontation of the First World War.
The German army proceeded south, heading for the important industrial city of Liège. But they met with further fierce resistance. Around Liège was a 46km chain of 12 forts, built in the late-1880s: six large strongholds (Barchon, Fléron, Boncelles, Flémalle, Loncin and Pontisse) interspersed with six smaller ones (Evegnée, Liers, Lantin, Hollogne, Embourg and Chaudfontaine), each about 4km from the next. Under a barrage of firing, the Belgian soldiers stationed there managed to hold back the invading troops and protect the city for 11 days. The last fort, Boncelles to the south, was taken on 16 August. Thereafter Liège was occupied by the Germans for the rest of the war. The German Kaiser HQ would settle for the duration of the war in nearby Spa.
Today Visé is a cheerful place. Yet in August 1914 much of it was burned down by German troops, who subsequently rounded up 650 civilian men and marched them off to work in Germany. In the 1920s the town was carefully rebuilt. Indeed on the main shopping street, Rue du College, a plaque marks the 1,000th house reconstructed in the town. It was completed in 1922.
Further along Rue du College is Visé's museum and cultural centre ( museedevise.be), housed in a former convent and containing an absorbing section on both the world wars. Meanwhile the Basse Meuse tourist board ( basse-meuse.be) is working on a circular driving and bike route in the area. When unveiled next year it will take in sites of the First World War battles with information panels from which further historical details will be accessible through smartphone barcodes.
Moving south, seven of the First World War forts, along with a few constructed for the Second World War, can be visited today – although some are open only sporadically (see liegetourisme.be for details). The most dramatic, and the most regularly open, is Loncin ( fortdeloncin.be) on the outskirts of the village of Ans. It is a tremendously moving site: you arrive at a sleepy-looking suburb and stop outside a small white museum building at 15 Rue des Héros. It contains a wonderfully eclectic range: genuine uniforms, the remains of shells, models of the forts and more. Guided visits can be booked in advance.
Behind, hidden in earthworks, is a huge triangular fort. In 1914 it housed 550 men. Like the other forts of the First World War it was designed by the military engineer Henri Brialmont and equipped with long-range howitzers in retractable cupolas. It was envisaged that the heaviest artillery to fire on these defences would be 210mm guns, but thundering along with the German troops were super-guns: 420mm howitzers shot from a cannon nicknamed Big Bertha. On 15 August 1914, a shell landed on the vault of Loncin's powder room and half the fort exploded. Nevertheless, 14 survivors continued fighting as the fort was overrun.
Loncin still lies in this part-ruined state – and visitors are allowed entry to much of it. Adding to the mood here, tours around the inner fortifications take place to a soundtrack of intensive shelling. Outside, stairs lead over the debris to the triangular tip of the fort which was turned into a striking crypt in 1921.
In total contrast to this sombre, thought-provoking site, today the centre of Liège – about 6km away – is a vibrant destination, renowned for its shops and its café life. Wander the Carré district, a pedestrian area of much charm, lined with neat boutiques and chocolate shops. Enjoy the lively art scene at Musée Grand Curtius ( grandcurtiusliege.be), a treasure house of beautifully displayed archaeology, religious works, sculpture and more; at Bal (Beaux Arts de Liège, beauxartsliege.be) with its contemporary shows; and at the intriguing museum of Walloon life ( viewallonne.be), wonderfully set in a former monastery. Then make for the historic heart of town around Place du Marché, order a locally brewed Jupiler beer at one of the cluster of bars and cafes here, and take in the vibe.
The bravery of the Belgium troops in the First World War became near legendary. In taking on the ferocious Germany army, they earned valuable time for the Allied forces. The French president sent a telegram to the Belgian king announcing that the city of Liège was to be awarded the Légion d'Honneur. And in the cafés of Paris, the dessert known as café viennois was renamed café Liègeois.
Jala Hotel (00 32 4 230 7330; jalahotel.com) at 2 Rue Jaspar is a contemporary-chic outfit with 54 very generously sized rooms. Doubles from €150, room only.
For an atmospheric, traditional meal head to Le Bistrot d'en Face (00 32 4223 1584; lebistrotdenface.be) on Rue de la Goffe opposite Liège's old butcher's guild. The menu offers a mix of fine French-style cuisine and a gastronomic twist on local specialities such as Boulets à la Liégeoise (meatballs cooked in Liège's apple and pear syrup). Or make for a local favourite: L'Enoteca (00 32 4222 2464; enoteca.be) in the Carré district at 5 Rue de la Casquette offers just one set menu based on what's available in the market that day.