When walking a forest path it is worth looking down and considering the surface. Here, on part of Langestaartdreef, you can see this was a working path, stone has been systematically laid. In times long gone, this would have carried horses and carts from Boitfort to Nysdam, La Hulpe and back, an important route that passed through the former Priory at Groenendaal.
It is now broken by roads and racecourses.
Its name? Nothing to do with horses but the shape of the lake at one end.