Castrejana Bridge

The Castrejana Bridge over the Cadagua River,[1]​ on the Coastal route of the Camino de Santiago, connects the banks of the Biscayan municipalities of Baracaldo and Bilbao. It is also called the bridge of the "Witches" or the "Devil." The bridge was built between 1435 and 1436, by the master Pedro Ortiz, from Lequeitio.[1]​ It played a very important role until the 19th century as part of the Royal Road that connected Bilbao and Castilla through Valmaseda and the Valley of Mena. The bridge is made with sandstone blocks forming a single semicircular arch. The abutments rest on the rocky banks of the river. The arch is the first element of the bridge to be constructed; in this case, the voussoirs are arranged in a double row.

Wikipedia