Only a few remnants remain of what was once a hated symbol of papal power, namely the Rocca Paolina. 

The imposing fortress was built in 1540 and majestic when the city lost much of its autonomy. The Lordship of the time, lost the battle against Pope Paul III Farnese. The construction of the fort was entrusted to Antonio da Sangallo and then continued by Galeazzo Alessi. The building took its place in the neighborhood of the Baglioni and for its construction were demolished hundreds of houses, many churches and towers. 

A first partial demolition took place in 1848 while the final after the unification of Italy in 1860. 

Today that building is so overwhelming just to the side of Via dell'Indipendenza up to Porta Marzia. Entering from the Etruscan port, with the escalators you get inside the fortress where you can still see the houses that Sangallo used to create in the base of the fortress. 

Looks like an entire underground city, with old courtyards, cisterns and ancient medieval houses built into the walls of the fortress. 

During the Christmas markets are set up in the Fortress with typical local products such as decorated ceramics.