Porta Palatina

The Palatine Towers (Italian: Porte Palatine; Piedmontese: Tor Roman-e) is an ancient Roman-medieval structure in Turin, Italy. The structure served as one of four Roman city gates, which allowed access from north to the cardus maximus, the typical second main street of a Roman town. They are located near the Duomo di Torino and Palazzo Reale.
In its current appearance, the building comprise two polygonal towers, of sixteen sides each, and a central gate. Only the latter is an original Roman structure, the towers having been added in the following years. The merlons are from 1404.

The name Porta Palazzo comes from the Latin Porta Palatii (“gate of the palace”), referring to the connected Imperial Palace, which housed numerous historical figures, including the Lombard kings and Charlemagne, and was later the seat of the communal authorities.
During the early eighteenth-century period of urban reconstruction in Turin, the gate was preserved only through the personal intervention of architect Antonio Bertola. It was one of the few ancient landmarks to be saved from destruction.
(Text taken from : http://en.wikipedia.org/wiki/Palatine_Towers )