Intermediate difficulty flow trail with a succession of sections built with mechanical means, in a series of sections in progressive difficulty, that will delight riders in technical progression who want to improve their skills in all types of modules and bike park style obstacles. From the trench line dug during the Civil War in the mountain range between Peña Castro and Sierro de las Meriendas, we take the first section of the flow trail. The trench line, although colonized by a young oak forest, is still visible for cyclists riding along R2 and R15. In fact, those riders coming along R2 from Llombera will have to wade the trench line a few meters before reaching the trailhead. Approximately, once we have passed the first third of the trail, we will follow a linking forest track that leads us to the next section of the flow trail that, from the NE slope of Alto de los Sierros de San Martín first, and then along its southern face, will lead us to the vicinity of Alcedo de Alba and La Robla. In the mountain range of Los Sierros, those who look for it will find a network of trenches not excavated but mainly erected using the rocks and boulders of Los Sierros themselves, which is certainly worth visiting.
