Greece · Attica

Lake Vouliagmeni

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Λίμνη Βουλιαγμένης

Lake Vouliagmeni is a small brackish lake south of Vouliagmeni on the Athens Riviera, fed by underground currents that seep through the mass of Mount Hymettus. It formed when the roof of a large cavern collapsed after an earthquake, and the outline of the collapsed roof can still be seen from a distance. Its warm water has made it a spa since the end of the nineteenth century.

How it formed

The lake was once a large cavern, whose roof fell in following an earthquake. Warm seawater flows into it through an underground channel in a network of flooded caves, so its temperature stays mild all year, while a freshwater spring lowers the salt content to brackish levels. The lake continues deep into the mountain as an underwater cave that has never been fully explored: its end seems impossible to trace even with sonar. Many underwater expeditions have charted it, and a few amateur divers have drowned in the attempt.

History

Because its water is constantly warm and rich in hydrogen sulphide, the lake has functioned as a spa since the end of the nineteenth century.

Nature

The lake is home to the only existing population of a species of sea anemone, Paranemonia vouliagmeniensis. The Greek state has declared it a natural monument, and it is part of the Natura 2000 network.

Gallery

4 photos

Photo: C messier · CC0

Photo: Dim Philos · CC BY-SA 4.0

Photo: Mmss60 · Public domain

Photo: Tzovara Erietta · CC BY-SA 4.0

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Visit

Getting there

Nearest settlement: Vouliagmeni

Swimming

No reliable information

Tips

The lake is used as a spa, so check the rules and the way to the water before you go. The cave under the lake is dangerous: do not dive in it without authorisation and experience.

Swimming in the thermal lake

The water is warm all year, reported at about 22–24 °C, so swimming works in any season, and the lake is also known for its fish treatment (a natural fish pedicure). Sunbeds are usually included with the entry ticket but go quickly at weekends, and towels are charged for, so bring your own. Early morning or late afternoon avoids the busiest crowds.

Opening and getting there

The lake is open from 08:30 to 16:30, with the last swimming ticket at 16:00; tickets and the winter hours are on the official website, lakevouliagmeni.gr. Bus 122 stops outside the lake, a few minutes’ walk from the entrance.