Stone

 In this particular area, we can see the ancient quarries that provided the limestone used in the building of  the Santiago Cathedral. Medieval pilgrims would carry as much of the stone as they were able approximately 75km. to the lime kilns. All along the way you see stacks of stones being left to symbolize the burden they carried. The ancient Roman roads have been deconstructed and the large flat stones used to provide a path up and out of the water.  

An enterprising person as all of this
had to be brought in on foot.