De Blankaart is a wetland nature reserve a few kilometres south of Diksmuide, centered on a lake fed by the Blankaart Polder. This flat, watery landscape of reed beds, marshes and flooded meadows was a no-man's land of a different kind during WWI — the deliberate flooding that stopped the German advance also shaped the hydrology of the whole area. Today it is one of the best birdwatching sites in West Flanders.
The reserve is home to a significant population of breeding marsh birds including bittern, marsh harrier, bearded reedling, and various warblers. In winter it attracts large flocks of waterfowl. An observation tower at the edge of the lake gives wide views across the polder landscape and out toward the distant dunes on a clear day. Walking and cycling routes thread the edges of the reserve; the Blankaartwandelroute is a well-marked loop of around 11 km.