This is probably the most important of Roman bridges in the world. In fact, its name Alcantara (Al Qantarat) means 'the bridge' in arab. That is enough to understand the value of this work. It was built between years 105 and 106 by Roman arquitect Caius Iulius Lacer on the Way that communicates Norba -today Caceres- with Conimbriga -today Condeixa-a-Velha-. Therefore it is not an access to a city. It is composed by six archs that imply a distance of 214 m. over the Tajo river. They are secured by five pillars and two supports at its ends. Its measures are really great: 48 m. high at its top: two central archs. Light of these archs is 27,34 m. for the 3rd and 28,60 m. for the 4th: they let the water run in the usual way. Prior and next archs are 2nd and 5th; they are 22,5 m. At last two extreme are 1st of 28,6 m. and 6th of 14m. These measures are not casual. They come from the necessity of saving a deep river with huge increases of its waters volume. The archs have two files of voussoirs: the upper is the lesser.