The use of silos, underground holes where grain and other materials were stored, dates back to ancient Greece. However, throughout history, many silos were no longer underground and started to rise as large towers.
In Spain, most of the large silos were built during the Francoist dictatorship. They are mostly found in the regions of Aragon, Castilla y León, Extremadura, and Andalusia, and they are so iconic that many know them as the cathedrals of the countryside. During the dictatorship, more than 600 silos were built, but the grain warehouses fell into disuse in the last few decades of the 20th century.