Lerna Heracles killed it, as the second of his labors. The strong Karstic springs remained; the lake, diminished to a silt lagoon by the 19th century, has vanished. Lerna is notable for several archaeological sites, including an Early Bronze Age structure known as House of the Tiles, dating to the Early Helladic period II (2500–2300 BC). The secret of the Lernaean spring was the gift of Poseidon when he lay with the "blameless" daughter of Danaus, Amymone. The geographer Strabo attests that the Lernaean waters were considered healing: Lake Lerna, the scene of the story of the Hydra, lies in Argeia
Lerna On-site techniques of flint-knapping with imported obsidian and chert attest to cultural continuity over this long stretch of time, with reduction in the supply of obsidian from Melos testifying to reduced long-distance trade at the end of Early Helladic III, corresponding to Lerna IV. Lerna has one of the largest prehistoric tumuli of Greece, accumulated during a long Neolithic occupation; then its crest was levelled and extended — as at Early Helladic Eutresis and Orchomenus— in a new settlement: this stratum, called Lerna III in the site's stratigraphy, corresponds with Early Helladic II at other sites. Lerna III lacks signs