The Kalmthoutse Heide is a cross-border river and drift dune area bordering the Brabant Escarpment.
This diverse and dynamic nature reserve consists of heathland, fens, forests and land dunes.The most beautiful examples are in the area of the Groote and Kleine Meer (Meersche Duinen), the Kriekelareduinen.
At the end of the last ice age, the sea level was much lower than today and a large part of the North Sea was dry. The area of the Kalmthoutse Heide was then part of a vast polar desert. In this dry and cold climate, the wind deposited over the entire landscape a layer of cover sand 1 to 2 m thick. During the Young Dryas, a last cold burst of the Ice Age between about 13,000 and 12,000 years ago, large quantities of sand from this Scheldt valley were blown up to the top of this area. The sand was deposited there in a belt of so-called river dunes, which is the widest in the Kalmthoutse Heide, at about 10 km.
That nature does not think or grow in boundaries is obvious. This nature reserve lies on both sides of the Belgian-Dutch border, northeast of Antwerp. It covers "only" 60 km², yet the area feels boundless, endless.