The ravelins are part of the second defense line of the Palmanova fortress: they are nine and are located beyond the moat; made to protect the curtains. The ravelins were built by the Venetian Senate, on a project by the engineer Verneda, in order to guarantee a higher defense system. The entire operation ended in 1682.

The ramparts of Palmanova are crossed by a system of underground galleries, some of which can be visited. The tunnels, built inside the ravelins, were called countermine galleries because, if necessary, they could be “mined” and explode to hit the approaching enemies.