De Maasduinen

The Maasduinen are dunes a river built and the wind then signed. At the end of the last ice age the Maas ran wide and braided here, dumping bare sand across its terraces; westerlies raked that sand into ranks of paraboolduinen — horseshoe dunes opening into the wind — stacked for over twenty kilometres along the river's east bank, the longest river-dune belt in the country. The park runs the ridge like a spine between two waters, the canalized Maas glinting to the west and the German border woods to the east, and the walking is genuinely up-and-down by Dutch lowland standards: crest, kettle, wet slack, next crest.

Poor sand made for a poor and therefore lucky landscape. Too meagre to plough, the dunes spent centuries as common heath and were then part-planted with mine-timber pine, so today's park is a weave of purple August heather, drift-sand blowouts still on the move, bog-rimmed fens in the dune hollows and old pine with black woodpeckers drumming through it. The warm south slopes carry Limburg's reptile wealth — sand lizards, smooth snakes, adders — and summer dusks belong to nightjars churring over the Bergerheide. At the heart of it lies the Reindersmeer, a sand quarry worked until the nineties and then let go: groundwater-fed and nutrient-poor, it has settled into implausible clarity, a lake with visibility measured in metres in a country of brown water, ringed by a path and off-limits to swimmers, which is exactly why it stays that way.

People are a thin, old presence. Well's moated castle at the park's edge — now, improbably, the Dutch campus of an American college — anchored the river villages; the Duitse Ring and other earthworks in the woods remember less friendly centuries; and the whole belt nearly became a NATO shooting range in the 1970s before Limburg objected its way to a park instead, formalized in 1996.

What's worth knowing before you go

The Maasduinen bezoekerscentrum sits by the Reindersmeer near Well, mid-park, with the lake loop (about eight kilometres) starting at the door; Bergen and Arcen serve the southern heaths, and Venlo is the practical rail-and-bus hub for the whole strip. Come in August for heather with nightjars still churring, or in clear winter light when the dune ranks read best. Paths are sandy and slow — count kilometres generously. The connoisseur's hour is the last one at the Reindersmeer's northern lookout, when the day-walkers have gone, the water turns to glass and hobbies hawk dragonflies over it until the light is out.