The Traiana Column is made of 19 blocks of marble caved inside in order to allow the passage of the winding stairways taking to the top, but also for the realisation of the tomb of the Imperator in the basement.

Nowadays, the structure is dominated by the statue of San Pietro, taking the place of the imperial statue of Traiano which went destroyed; it roughly reaches 40 metres of highness with a diameter of approximately 3.5. The most interesting part of the Traiana Column is obviously the decoration in bas-relief that evolves as an helicoidal papyrus along the column, and which describes the campaign of Dacia, illustrating in addition to more than 2500 figures, scenes of everyday life and war life.
The didactical intent of the work is confirmed by the expedient technique used by the Latin maestros who, to correct the loss of definition due to the distance of the bas-relief from the eye of the observer, as the frieze unrolls towards the top, they increase the dimensions.