Thanks to its volcanic history, the island of Ustica offers awesome opportunities for deep diving. Notable sites include Scoglio del Medico and Grotta dei Gamberi. Snorkelers can explore Grotta Azzurra, Grotta Verde, and Grotta delle Barche. There are plenty of dive centres that can offer guided trips to all of these watery hotspots. Once you dry off, check out the prehistoric ruins of a large village that dates to the Bronze Age. Houses in the main square are painted with colourful murals, giving the whole village an artsy vibe.