The seven basalt stacks rising off Aci Trezza are roughly 500,000 years old — older than Etna's present cone, and formed underwater before the sea withdrew from them. Homer gave them a different origin. In the ninth book of the Odyssey, the blinded Polyphemus hurls boulders after the departing ship, and those boulders became the Faraglioni dei Ciclopi. Sicilians have called the shoreline the Riviera dei Ciclopi ever since. A catania yacht tour crosses the same water in an afternoon. The coast north of the city is a geological archive. Lava that reached the Ionian in successive eruptions cooled on contact and fractured into columnar basalt, the same hexagonal jointing found at Giant's Causeway. At Aci Castello a Norman fortress from 1076 sits directly on one of these black flows, its walls indistinguishable in colour from the rock beneath. Further north the Timpa di Acireale drops nearly 200 metres to the water, a fault scarp now protected as a nature reserve. The sea below holds posidonia meadows, sea urchins, and visibility that regularly exceeds fifteen metres in summer. Catania itself owes its shape to the same volcano that shaped the coast. The 1669 eruption buried much of the western city and pushed the shoreline seaward by more than a kilometre, stranding older harbour works inland. The 1693 earthquake levelled what remained, and the rebuilding under Giovanni Battista Vaccarini produced the Baroque of Via Etnea and Piazza del Duomo in pale limestone and black lava, a UNESCO-listed pairing. The modern Porto di Catania, on Via Cardinale Dusmet, occupies ground the lava made. Seen from the water, that history resolves into a single frame. The Baroque skyline sits low; behind it Etna occupies the horizon, snow-capped for much of the year, at 3,300-odd metres the tallest active volcano in Europe. Catania yacht tour tours trace this line north toward Aci Trezza and, on longer sailings, as far as Isola Bella beneath Taormina — the pebble isthmus that Florence Trevelyan planted with exotics in the 1890s and left as a private garden. The sailing tradition here is working rather than ornamental. Aci Trezza's fleet still lands anchovies and swordfish, and Giovanni Verga set I Malavoglia among those families in 1881. What operators now sell as leisure — a Sicilian aperitif taken at anchor, a snorkelling stop under the stacks — follows routes the fishermen drew first. A catania yacht tour is, in that sense, an old itinerary in newer hulls.