The Contreras Port and Bridge, built by Lucio del Valle in 1853, are a magnificent feat of engineering, the most valuable historic highway in Spain. Located in Cuenca (Castile-La Mancha), it was an important road connecting Madrid and Valencia until 1970. It has 180 degree curves until to the bridge that crosses the river separating Castilla from Valencia. The Castilian-Manchego section was renovated in the 1990s.