Optical telegraph towers of the Ebro Historical milestone · Nonaspe, Bajo Aragón-Caspe, Zaragoza Image of Nonaspe, not of the place itself. During the 19th-century Carlist Wars, optical telegraph and watch towers were built along the Ebro and the Matarraña, allowing warnings to be relayed between detachments. Several of these structures are preserved within the municipal area of Nonaspe. siglo XIX Photo: Juan Emilio Prades Bel (CC BY 4.0) What to see and do in Nonaspe