In its prime, Syros had its own currency, which was more valuable than the Greek drachma. The local economy is not dependent on tourism, even today. Most visitors are Greeks. Admittedly, the southern coastline has suffered from over-development and the beaches are rather disappointing. But in the rugged, untouched north, dirt tracks link secluded hamlets and footpaths lead to sheltered bays. Children pootle around on Kini beach, while their parents swig ouzo at the pair of tavernas beneath the tamarisk trees. It's the kind of place where you could stay all day, waiting for the sun to set at the mouth of the bay.
Instead, I climb aboard Perla for a whistlestop tour of the northern beaches with Captain Lakis. He is in infectiously high spirits, swaying his hips to Cuban music as we cruise past a succession of idyllic bays: Delfini, Varvaroussa, Aetos, Lia, Dyosmos, Marmari, Grammata. Pressed to pick my favourite, I settle for Marmari, where Lakis has planted a few palm-frond umbrellas. I dive off the boat into the water and drift towards the shore, melting into the landscape. It seems that life couldn't get any better, when Lakis whips out his pièce de résistance: an ingenious floating bar, with round holes for wedging plastic cups of ouzo and ice. He has even rustled up some mezze: cheese, tomatoes, and cherries. We stand in the waist-deep water and toast our good fortune.
Rachel Howard is the co-author of 'Secret London: An Unusual Guide' (Jonglez Guides, £10.99), out now
Continued: where to stay in Santorini
Pictured: Allou-Yialou restaurant in Syros