Behind Laredo, the N634 winds up into the hills, with views of the Bay of Santoña over your shoulder. A short drive, parts of it within sight of the coast, takes you into the fishing village of Castro-Urdiales, believed to be the oldest settlement on the Cantabrian coast. Castro-Urdiales (castro was the Celtiberian word for a fortified village) was the region's leading whaling port in the 13th and 14th centuries, when it had almost three times today's 13,000 residents. Now it's known mainly for its seafood.