Best mountain biking trails in Zittau

Varied mountain bike tour near Zittau in Saxony. This MTB tour begins at Lake Olbersdorf - a successfully recultivated remaining hole of a former brown coal open-cast mine - and leads into the Zittau Mountains. It's varied, sometimes steeply uphill (the steepest gradient to Niederoybin is almost 20%), down on fun descents and over partly heavily blocked routes and single trails. The route is marked with red dots on the trees. It is nice to swim at Lake Olbersdorf in the summer...