In the deep south of Belgian's province Namur you'll find a famous sink hole in the middle of Viroin Nature Reserve: Fondry des Chiens. The yellow indicated 8 km hike will lead you over steep forest paths passed highlights like an old steam train railway, a viewpoint where you can spot falcons and the famous sink hole creating a 20m deep canyon. Everyone who saw the Netflix series 'Arcadia' will recognize this canyon from the series!