It is a Roman arch bridge crossing the Tagus River built between 104 and 106 in the town of Caceres Alcantara. It consists of 6 arcs of unequal height, which rest on five pillars to turn at different heights in the field of slate rock raided. There is a commemorative shrine with an arch of triumph at the top center of the bridge with a height of 10 m, called Trajan. The bridge is made of rusticated blocks of granite rock between 45 and 50 cm. In addition to the foot of the bridge there is a small Roman temple dedicated to the same constructor, call Lácer and Christianized in the Middle Ages with the name of San Julian. Then he added a steeple and a cross supported by four granite skulls. He is buried in this work the architect Gaius Julius Lacer. An inscription in the center of the bridge indicates that it was built in honor of the Roman Emperor Trajan, born in Hispania. The inscription reads. In his meriodional entry is recorded in another inscription that his engineer was Key Julio Lacer. Alcantara Bridge was built by seven lusitanas taxes villas and tried to unite the road of Norba (Caceres) to Conimbriga (Condeixa-a-Velha) and station Via de la Plata. The name comes from the time of Muslim invasion in the Middle Ages as "al-Qantarat" (القنطرة) means "bridge" in Arabic.