Rocca Tiepolo played a key defensive role during its time. Now a historic attraction, you can just imagine some of the scenes its fortified walls have witnessed.
You're spoiled for sightseeing choice when in Porto San Giorgio. Rocca Tiepolo is an ideal place to start here, but there are loads of other worthy sights to consider. Teatro dell'Aquila, Port of Porto San Giorgio, and Duomo di Fermo are not far from the history-filled fortress and will fill in your day nicely.
