't Ham is a nature reserve in the valley of the Groote Molenbeek. In the south it borders the forest area Reulsberg. The Groote Molenbeek, which flowed through the original area with plots of grassland and coppice walls, was straightened in the course of the 20th century. The moist area turned out to be unsuitable for intensive agriculture, so the landscape has been preserved. In the early 21st century, the area came into the possession of Staatsbosbeheer, who allowed the stream to meander again and the area was given a nature destination. The Reulsberg on the edge of 't Ham is a higher wooded area of drifting sand. Ter Horst Castle Park is a park-like landscape around the ruins of the Huys ter Horst castle. The area used to be known as Moelbaerenbos and later as Kasteelse forests, the name Moelbaerenbos is derived from blueberries (moelbaeren) that used to occur frequently in the forest. Huis Ter Horst dates from around 1350, from 1820 the castle fell into disrepair and was never rebuilt. At the start of the hike you pass the Melderslose ruin from 1938 near the Vlasven. It is not a real ruin, but a fake castle ruin or folly (a folly or follie is a non-conventional building or structure) that was to serve as a country retreat for the Jonge Wacht t, an association for boys between the ages of twelve and seventeen. Het Vlasven is one of the three Places of Happiness that one encounters during this walking tour, the other two are 't Ham on the banks of the Groote Molenbeek and 't Aendekuulke, a fen with a real duck decoy in the Ter Horst Castle Park.