The Molenbeek Valley in Jette and Ganshoren is one of three designated special areas of conservation in the _Brussels-Capital Region within the European Natura 2000 network. The main core sites include the Poelbos and Jette marsh regional nature reserves. The Poelbos nature reserve (9 hectare) is mainly composed of an old sandstone quarry, once operated by the monks of Dieleghem Abbey and subsequently replanted with trees. Various springs surging from the bottom of the small valley feed a fish pond (enclosed within the reserve) as well as the adjoining Jette marsh (5 hectare). The marsh was significantly modified by the construction of a wastewater sewer and was restored during the creation of King Baudouin Regional Park. It now contains a large variety of habitats (open water lakes, reed beds, wet meadows, willow woods). A walking tour that will enable you to discover the natural side of Jette.