Fortification of the salt works Historical milestone · Arcos de las Salinas, Gúdar-Javalambre, Teruel Image of Arcos de las Salinas, not of the place itself. The salt pans had been in activity since the middle of the twelfth century and in 1357 they were fortified, turning the structure of the well into a defensive tower. Recent excavations have documented salt production as early as the Bronze Age. 1357 Photo: 19Tarrestnom65 (CC BY-SA 4.0) What to see and do in Arcos de las Salinas