#1. Bouillon

Dreamily arrayed around a tight loop of the Semois River, Bouillon is dominated by the gnarled ridge-top ruins of a sturdy medieval castle. On a summer evening, limpid light and reflections in the shallow water can make this one of Belgium's prettiest towns.

Slouching like a great grey dragon high on Bouillon's central rocky ridge, Belgium’s finest feudal castle-ruin harks back to AD 988, but it's especially associated with Crusader knight Godefroid de Bouillon, the first 'Belgian' ruler of Jerusalem.

The super-atmospheric site has everything you might wish for in a castle: dank dripping tunnel passages, musty half-lit cell rooms, falconry displays, rough-hewn stairwells and many an eerie nook and cranny to discover. Plus there are off-beat surprises like maturing cheeses and a caligraphy mini-museum.