This castle, west of Piazza Duomo, was once the proud fortress of Frederick II in the 13th century. When it was originally built, the grim-looking fortress, surrounded by a moat, stood on a cliff overlooking the Ionian Sea. But Mount Etna's lava has shifted the land over the centuries. Now landlocked, Castello Ursino is reached by going through a rough neighborhood where caution is advised.

The castle was built on a square plan with a keep 30m high (98 ft.) on each corner and semicircular towers in the middle on each side. If you walk along the perimeter, you can still see the old moats and even some Renaissance windows embedded in the south side.

The castle's pinacoteca (portrait gallery) has an interesting (though unspectacular) series of paintings that date from the 1400s. Most of the work is from Sicily or southern Italy, including Antonello de Saliba's polyptych of the Madonna; de Saliba was a pupil of the legendary Antonello da Messina. One of the best-known Catanian artists was Michele Rapisardi, who is represented by two lovely studies: The Testa di Ofelia Pazza (Head of the Crazed Ophelia) and a depiction of the Sicilian Vespers. Surely the saddest La Vedova (Grieving Widow) in all of Catania was that depicted by another homegrown artist, Giuseppe Sciuti. The art of Lorenzo Loiacono is also worth noting for his vivid, even theatrical efforts.

Housed inside the Museo Civico are Prince Biscari's archaeological collection, along with objects from San Nicolò Monastery, and some of the best Sicilian painted carts on the island.