From Brussels: Wallonia Fortress Cities — Namur, Bouillon, Huy & Dinant

Head southeast from Brussels toward the Namur province, leaving the flat Brabant plateau and descending into the Sambre valley. The guide introduces Wallonia's strategic geography: the Ardennes plateau, cut by the deep valleys of the Meuse and its tributaries, created a natural defensive landscape where river confluences and gorge narrows became fortress sites used continuously from prehistoric times to World War II.

The Citadel of Namur stands on the rocky spur between the Meuse and Sambre rivers — one of the most defensible positions in northern Europe. Settlement and fortification on this site began in prehistoric times; the medieval castle was developed from the 10th century by the Counts of Namur; and the massive system of bastions, casemates, and tunnels covering the entire hilltop was constructed and reconstructed by the Spanish, French, Dutch, and Belgian armies from the 1670s to the 1940s. The citadel covers 4km of fortifications — one of the largest in Europe. During World War I, German forces attacked Namur in August 1914; during World War II, they occupied it as a military headquarters.

Huy is a medieval river town on a loop of the Meuse that made it the strategic key to the entire valley — whoever held Huy controlled all river traffic between Namur and Liège. The old town retains remarkable medieval architecture including the Gothic collegiate church, the 14th-century grain hall (La Bassinia, one of the oldest surviving market halls in Belgium), and the Fort of Huy above — a 19th-century Prussian-designed replacement of the earlier medieval fortifications. During World War II, the Fort of Huy was used as a Nazi internment and transit camp; a memorial museum now occupies part of the site.

Château de Bouillon in the deepest Ardennes is one of the oldest feudal fortresses in Belgium — built on a dramatic meander of the Semois river that makes it almost impregnable by natural geography. The castle is inseparable from the name of Godefroy de Bouillon, the duke who sold it to the Bishop of Liège in 1095 to finance his participation in the First Crusade called by Pope Urban II. Godefroy led the crusading army from this valley to Jerusalem, which fell in July 1099. He died there in 1100, having refused to accept the title of King of Jerusalem ('I will not wear a crown of gold where my Saviour wore a crown of thorns'). The castle he sold is still standing, with a wax museum recreating the crusade's story.

Dinant's citadel clings to a 100m-high limestone cliff above the Meuse — a vertical fortress accessible only by cable car or by 408 steps. The site has been fortified since at least the 7th century; the present structure dates from the Spanish and Dutch periods (17th-18th century). Below the cliff, Dinant is the birthplace of Adolphe Sax (1814-1894), inventor of the saxophone — the bridge over the Meuse is lined with oversized saxophones in his honour. In August 1914, German forces massacred 674 Belgian civilians here during their advance — one of the defining atrocities of the opening weeks of World War I.