GR 573, Vesder and Hautes Fagnes (Belgium)
Like all the GR routes in Europe, this route is a well established long distance walking path. GR meaning grande randonnée which literally translates to 'grand route'. They are well known for their typical white/red route markers. Most GR-routes run over very long distances, often passing through entire countries.
This one however is a local GR-route, making (kind of) a loop through one region, namely the eastern part of Belgium. While doing so it crosses through different geografical zones.