Claim: Helike was affected by a tsunami.

Helike -LRB- -LSB- ˈhɛlᵻkiː -RSB- Ἑλίκη , pronounced -LSB- heˈlikɛː -RSB- , modern -LSB- eˈlici -RSB- -RRB- was an ancient Greek city that was submerged by a tsunami in the winter of 373 BC . It was located in Achaea , northern Peloponnesos , two kilometres -LRB- 12 stadia -RRB- from the Corinthian Gulf and near the city of Boura , which , like Helike , was a member of the Achaean League . Modern research attributes the catastrophe to an earthquake and accompanying tsunami which destroyed and submerged the city . In an effort to protect the site from destruction , the World Monuments Fund included Helike in its 2004 and 2006 List of 100 Most Endangered Sites .