The city that sank

Olous was one of the hundred cities of ancient Crete, inhabited from Minoan times, with its own coinage and its own government. Most of its coins show Britomartis, the Cretan Artemis, on one side and Zeus on the other.

At some point the land subsided and the city went under. What survives lies in shallow water at Poros — sections of wall, foundations, and a long structure that archaeologists think was the city wall. Underwater surveys have mapped parts of it, but it has never been properly excavated.

You can see some of it while swimming, on a calm, clear day.

The mosaic

On the shore stands the early Christian basilica of the fifth century AD, probably the cathedral of Olous. It has three aisles, and part of its mosaic floor survives.

The mosaic is one of the finest of its kind in Crete: geometric borders, plants, and figures of fish, dolphins and birds. Set into it are inscriptions naming the people who paid for it — each of them contributed half a gold coin.

French naval forces stationed at Poros found the first fragment in 1897. The French Archaeological School excavated in 1937, and the full excavation followed in 1960.

A second basilica of the fifth or sixth century stands near Kolokytha beach, found in 1971. Its mosaics have been destroyed by the sea, but the white marble fragments remain.

Salt, and a canal

The Venetians took the harbour and built salt pans here around 1200. They produced high-quality salt for five centuries, and they were still working until 1972. You can still see the dozens of walled basins in the shallow water.

The canal at Poros is much later. The French navy cut it in 1897, during the international occupation of Crete, to connect the Elounda lagoon with Mirabello Bay. A stone arched bridge crosses it, and three stone windmills stand beside it — all three are listed monuments.

The whole area — the sunken city, the mosaic, the salt pans, the canal and the windmills — is a protected archaeological zone.

Elounda beach, in the town, is sandy, shallow and organised — the straightforward choice with children.

Plaka, a few kilometres north, mixes sand and pebble and looks directly across to Spinalonga. Many visitors swim there and take the boat from the same spot.

Kolokytha, at the end of the peninsula, is a sheltered cove reached on foot or by boat, and the water there is exceptionally clear.

Chiona, on the road towards the canal, sits beside the salt pans and the archaeological zone.

Diving is genuinely established here. A dive centre has worked out of Elounda for around thirty years and runs trips to more than twenty-five sites around Mirabello Bay, and several of the large hotels have their own PADI centres.

The dive that belongs to this place is over Olous. Because the sunken city lies in shallow water, snorkelling trips run to it and you need nothing beyond a mask.

Boats to Spinalonga leave the harbour through the day in season, and smaller craft can be hired for the bay.

On land, a marked route runs out along the Kolokytha peninsula from the canal, past dry-stone walls and old terraces, to a sheltered beach at the far end. It takes a couple of hours there and back, with no shade at any point, and Spinalonga is in view for much of the way.