The sulphur mines of La Azufrera Historical milestone · Libros, Comunidad de Teruel, Teruel The extraction of sulphur was the main industry of the municipality in the nineteenth century and gave rise to a mining quarter of its own, La Azufrera, today disappeared. In 1847 the village had six hundred and thirty inhabitants thanks to that activity. siglo XIX Photo: Alfredo SÁNCHEZ GARZÓN (CC BY-SA 4.0) What to see and do in Libros