Hidden beneath partly-wooded hills 1.7km southwest of Hotton, the Grottes de Hotton are some of Belgium’s most awesome caves. Sculpted grottoes sprout pretty stalagmites and weird ‘eccentrics’ – mini corkscrews or horizontal protrusions apparently defying logic. However, the real highlight is descending a former siphon through upturned vertical strata into a dramatically narrow, 37m-high subterranean chasm. Guided visits (think 80 minutes) can feel overly long and aren't necessarily in English. Tours depart roughly hourly in summer; otherwise call to check departure times. Dress for 12°C and prepare for 580 steps.
