Here we are in a fine Norman castle, on what used to be an island, but was later connected by a large lava flow out of Etna:
This is meant to look like Mark being a Cyclops, throwing a large rock at a ship… The rocks you can see in the distance behind the castle are said to be those thrown by Polyphemus at Odysseus as he escaped with his ship…
Indeed Aci Castello is named after the castle and the river Aci, said to be what remains of Acis, a favoured rival killed by Polyphemus when he was rejected in his suit for Galatea.