Castelvecchio, originally called Castello di San Martino in Aquaro, is a castle in Verona currently used as the civic museum, it is the most important military monument of the Scaligera lordship.

The whole of the castle is dominated by the high bulk of the Keep, which stands on the western front, on the banks of the river Adige, near the fortified bridge. Still in the eighteenth century, the large frescoed image of the lion of San Marco, symbol of Venetian dominion, stood out on the eastern face. In the Habsburg era, the tower housed the military optical telegraph station, in communication with the signaling network established between the fortresses of the Quadrilatero. The signaling devices, day and night, placed on the roof terrace, were in connection with the corresponding devices placed on the Torre della Gabbia, in Mantua, and with those of the telegraph tower of Pastrengo, on the San Martino hill. Tangent at the base of the Keep, the bridge with three large unequal arches crosses the river, with the very audacious impetus of the main arch, on the span of 48.69 meters. Even today the bridge imposes itself on the observer as a masterpiece of art.