Helike (; , pronounced , modern ) was an ancient Greek polis (city-state) that was submerged by a tsunami in the winter of 373 BC. It was located in the regional unit of Achaea, northern Peloponnesos, two kilometres (12 stadia) 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. History Helike was founded in the Bronze Age, becoming the principal city of Achaea. The poet Homer states that the city of Helike participated in the Trojan War as a part of Agamemnon's forces. Later, following its fall to the Achaeans, Helike led the Achaean League, an association that joined twelve neighboring cities in an area including today's town of Aigio. Helike was a small town with only 5,000 year-round residences, it became powerful due to its patron god Poseidon. Helike, also known as Dodekapolis (from the Greek words dodeka meaning twelve and polis meaning city), became a cultural and religious center with its own coinage. Finds from ancient Helike are limited to two fifth-century copper coins, now housed in Bode Museum, Berlin. The obverse shows the head of Poseidon, the city's patron, and the reverse his trident. There was a temple dedicated to the Helikonian Poseidon. Ancient Greeks would travel to Helike to be blessed by Posidon and to trade. Helike founded colonies including Priene in Asia Minor and Sybaris in Southern Italy. Its panhellenic temple and sanctuary of Helikonian Poseidon were known throughout the classical world, and second only in religious importance to Delphi. Destruction The destruction of Helike is now debated by many people in academia. There is a version that many ancient sources accept, but now because of science and technology, there is a new theory coming to light. The theory is that there was a earthquake that caused soil liquifaction and then mudslides. The mudslides and earthquake combined with a lot of rain that ended up flooding Helike. The ancient account of Helike's destruction in 373 BC, two years before the Battle of Leuctra, during a winter night. Several events were construed in retrospect as having warned of the disaster: some "immense