The Puente Ingeniero Carlos Fernández Casado -which takes its name from the construction engineer - spans the Barrios de Luna reservoir, in the province of Leon. It was built between 1981 and 1983 as part of the AP-66 or Ruta de la Plata motorway. It is a cable-stayed bridge, measuring 643 metres long and 22 metres wide, for four lanes, and was the longest cable-stayed bridge in the world at that time. It has two towers more than 100 metres high, which open at the bottom. Each tower has 27 pairs of front cables and 28 pairs of rear cables. The bridge is divided into three spans, the central span measuring 440 metres and the two side spans measuring 66 metres. A sliding joint was built into the central span to absorb expansion movements.
Carlos Fernández Casado (Logroño, 1905- Madrid, 1988) was one of the most prestigious and innovative civil engineers in his profession. From the outset, he specialised in resistant bridge structures, researching new materials in his own laboratory. Professor of Bridges, he examined archives and libraries and travelled the roads of Spain to classify bridges, Roman roadways, aqueducts and other civil engineering works to lay the foundations of the history of engineering.
The Roman bridge in the city of Mérida stands on the Guadiana river as part of the archaeological site of the ancient Augusta Emerita, the name by which the town was known in ancient times. It was built in the 1st century to facilitate communications with Hispania Baetica and give access to the city after the settlement of the Roman legions in town. It is 792 meters long with 60 round arches and it is considered to be the longest bridge of antiquity. It is built with a concrete core made of materials from the river and covered with granite padded blocks. It was originally divided into three distinct sections. The location where the bridge was raised was chosen taking into account the lower flow in that part of the river and because of the fact that the course was divided into two surges with an island in the middle which served to support the bridge. Over two thousand years of flooding and overflowing of the river have led to several restorations although the bridge still keeps its original construction in the part closest to the city known as the Humilladero.The souvenir sheet depicts a view of the Roman bridge with its many arches.
The Puente del Pilar, also known as the Iron Bridge crosses over the River Ebro in the city of Zaragoza. It was built in the late 19th century by the Spanish engineering company La Máquina Marítima y Terrestre specializing in the manufacture of metal bridges in the second half of the 19th and early 20th centuries. It was one of the first fixed bridges in Zaragoza since up till then the only fixed bridge in town was the 15th century Puente de Piedra. In 1991 it underwent a restoration directed by civil engineer Javier Manterola in which two arched side boards were added for the passage of vehicles reserving the central platform for pedestrians. The metal structure was painted in blue and white, the colours chosen in a popular vote.