Pietrarossa Castle is mostly a ruin now, but the setting still explains why this was the city's old strong point. Its surviving towers stand on red rock above the Angeli district, looking over the Salso valley and the older road approaches to Caltanissetta.
The castle is usually linked to the Arabic roots of the city's name and was already important in the medieval period. An earthquake in 1567 destroyed much of it, leaving a fragment that feels more dramatic than polished.