The fortress, part of which is carved into the rock, can be seen from the highway. If you go up by car or using the funicular, you can enter it directly upon arriving at the upper station. The entrance is on the left as you exit the station.

It was built in the 14th century by the Spanish military leader and architect Albornoz, who was commissioned to reconquer territories for the Holy See, which was planning to return from Avignon and fortify them. The fortress underwent several modifications and periods of destruction, and today it serves as a public garden for residents and tourists, as well as an excellent vantage point overlooking the entire valley below, the Umbrian hills, and the Autostrada del Sole, which connects northern and southern Italy.

It is worth looking down at the fortress walls and seeing the road that once led all those who wished to enter the city.