Trajan's bridge was built between the end of the 1st century and the beginning of the 2nd century AD, along with the development of the thermal baths, it is one of the best Roman legacies of ancient Aquae Flaviae, which still prevails today, resisting historic floods, and to the strong currents of the river.

With approximately one and a half meters in length and a dozen visible arches, the works carried out in the 1930s covered some of the arches and others still buried in the construction of the houses implanted there and overlooking the river.

 According to Antonio Rodríguez Colmenero, it is one of the few bridges in the Peninsula that have a construction date, to be believed in the column dedicated to Trajan, existing upstream of the bridge. The Roman sidewalk recently discovered next to the bridge, upstream and obliquely arranged in relation to it, must be before the bridge.

In one of the last reforms it underwent, at the end of the century. 19, a cutlery was replaced, substantially in the middle, on each side by a semiculular pillar, on which were placed commemorative, monolithic, cylindrical and inscribed marks, constituting copies of the original lost patterns.