La Unión or Siega Verde bridge

The La Unión or Siega Verde bridge (local road SA-V-88 from Castillejo de Martín Viejo to Villar de la Yegua) over the Águeda River, seen from downstream. The engravings are identified on the rocks on the left bank (to the right in this photo), over the course of a little more than a kilometre. From the town of Ciudad Rodrigo to the mouth of the Agueda river in Duero, in about 60 km, there is no other river passing, which runs embedded in a rugged terrain. This is a natural ford that should have been used over time.