The Castle of Aci Castello is a fascinating medieval fortress located on a lava rock promontory overlooking the sea, in the town of Aci Castello. The castle is entirely built of black lava stone, originating from the flows of Mount Etna, which gives the structure a severe and imposing appearance. It stands on a solidified lava promontory, the result of an ancient volcanic eruption, and dominates the Ionian Sea. Its construction likely dates back to the 7th century, but the current structure was built by the Normans in 1076 on top of a pre-existing Byzantine fortification. It was strategically positioned to control the Ionian coast of Catania, with a defensive role over the gulf and the city of Catania. 
Today, the Castle of Aci Castello is open to visitors, and from its terrace, one can enjoy a breathtaking view that stretches across the Riviera dei Ciclopi and Mount Etna.