Chalkida and the Euripus Strait

The Euripus separates Evia from the mainland and narrows at Chalkida to about forty metres, where the tidal flow behaves unlike anywhere else in the Mediterranean: the current runs one way for around six hours, slackens, then reverses, at speeds that can reach eight knots, and during certain phases of the moon it can switch direction more than a dozen times in a day. Aristotle studied it and, by one persistent legend, drowned himself in frustration at failing to explain it, which is untrue but tells you how the phenomenon was regarded. Modern explanation involves the different tidal timings of the two basins on either side. The old sliding bridge retracts to let ships through, and cafes line both banks, where locals sit and watch the water change its mind.

What you actually see

• The reversing current - water visibly running one way, then the other.
• The sliding bridge - a road bridge that retracts for shipping.
• The waterfront cafes - terraces on both banks facing the channel.
• The Karababa fortress - a seventeenth-century fort on the mainland hill above.

When to go

Any time; the reversal happens daily, and cafes post the expected times. Full and new moon periods produce the most erratic behaviour, which is when the water is most interesting to watch.

Honest expectations

The strait is a phenomenon, not a spectacle: the current changes over minutes and looks like a fast river reversing, which some visitors find underwhelming. Chalkida is a busy provincial city with traffic and ordinary architecture beyond the waterfront.

Nearby

Eretria and its ancient site lie south on Evia; the beaches of northern Evia are up the coast.