Rocca Paolina

Commissioned by Pope Paolo III in the 1540s, this fortress wiped out entire sections of a formerly wealthy neighborhood. Its insides have long since been hollowed out to make way for scale mobili (escalators) up to the historic center, but it's still a fascinating sight with its mighty walls, moody lighting and dark nooks and crannies, and is sometimes used to host temporary exhibitions. Up above is a small park, the Giardini Carducci.