Caves of the Ardennes
Large areas of the Ardennes consist of karst – areas
of soft, porous limestone that, over the centuries,
have been gouged out, tunnelled and dissolved by
rivers, streams and rain. In numerous places, this
has created honeycombs of underground passage-
ways and galleries, some still filled with lakes and
rivers and containing fantastical arrays of stalactites
and stalagmites. The best of these caves, or grottes,
have now become major attractions. Visitors are led
deep into the landscape, sometimes in boats, to see
these extraordinary sculptural formations under dra-
matic illumination. There is evidence too, that some
of these caves were shelters for prehistoric people.208 BELGIUM AND LUXEMBOURG REGION BY REGION
The Grottes de Hotton (see p226) form a network of
deep, underground passages. Narrow paths lead down
to a succession of dripping galleries draped with sculp-
tural limestone, noted for its extraordinary range of
delicate shapes and colours. The base is flooded by a
siphon that marks the modern water table.Grottes de Goyet at Gesves, occupied
by Neanderthals 40,000 years agoGrotte la Merveilleuse in Dinant is
celebrated for its “frozen waterfalls”:
stalactites and stalagmites with the
glistening limestone seemingly cap-
tured in mid-flow. Guided tours,
lasting about 50 minutes, lead visi-
tors through successive chambers
via a series of pathways and steps.CAVE SYSTEMS
The limestone caves of the Ardennes are celebrated for
their astonishing range of concretions of fused stalactite
and stalagmite. Streams that are formed by surface water
enter cave systems through a sink hole, replenishing the
underground rivers. Water dripping through the cave
ceiling deposits particles of limestone that slowly build
up stalactites, and corresponding stalagmites on the cave
floor. The underground river, on a bed of harder rock,
continues to carve a path through the softer limestone.Sink holes allow water into
the bed of limestone.