Like most of the wetlands in the Haine valley, the Harchies-Hensies-Pommeroeul marshes were formed in subsidence caused by mining. The depressions were formed in the mid-1920s and immediately filled with …
The old quarries of the Dendre and Congo are a historic site of exploitation of blue stone, or "small granite", from the 18th century until 1951. Today submerged, they form …