The main entrance of the structure is very pretty and consists of a facade of Carrara marble. The main door entrance, designed by Simone Moschino and built by GB Carra in 1596, has been preserved without subsequent additions.
La Cittadella was originally designed for defensive purposes complete with ramparts and moats. The structure was later used as military barracks, a political prison and as a place for capital punishment.
All this testosterone infused purposing makes it a bit ironic that in the late twentieth and early twenty-first century, the fortress was restored and is now used as a public park with space dedicated to sports and activities for children. I can't help but hope that all the happy children noise and energy has somehow karmically purged the old bloodthirsty vibes.
UPDATE: Joe and I saw an old map of the city which showed that all of Parma was walled with La Cittadella outside the city. Further investigation - La Cittadella was the army barracks and training grounds.