The Canal de Castilla begins in Alar del Rey, an illustrious work of 18th century hydraulic engineering that was an important vein of communication, commerce and prosperity in much of the Castilian lands for a century. In 1860 the railway monopolized the trade in cereals, goods and minerals in the north of Castile and transport barges stopped using the canal, which continued in use until the mid-20th century, exploiting the hydraulic energy of the locks and irrigation systems. . The starting point is the dock of the old piers of the Canal de Castilla, a very pleasant place to start a gravel trip of a couple of days of bikepacking along the Palentino Romanesque Natural Path, which largely coincides with the Ruta del Coke charcoal. “Cok” or coke is a high-quality hard coal with good heat capacity that is highly appreciated in the metallurgical industry. The best coke deposits were in exclusive mines in Fuentes Carrionas and Montaña Palentina, mainly in the valleys of Mudá, Castillería and Santullán. The extracted mineral was transported by horse and cart to the piers of the Canal de Castilla bound for Valladolid and Palencia, where distribution began. The cycle tour follows the old mining road to the mountains of northern Palencia, visiting a few rural Romanesque jewels. Before leaving we passed by the milestone where the Canal de Castilla takes its water from the Pisuerga River. I discovered this beautiful river spot thirty years ago, when I cycled along the canal towpaths for the first time. Now we leave in the opposite direction following the red posts of the Nature Trail. The roads are good for gravel cycling, the relief is a bit leg-breaking and there are several hard slopes that warm up the muscles with the gravel single chainring but the surface is great.