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
Drakaina (mythology) generally slain only by gods or demigods. Zeus slew Delphyne and Campe, Apollo slew Python, and Argus Panoptes slew Echidna. Echidna was the mother of a huge brood of monsters, including other dragon-like creatures. According to Hesiod, Echidna gave birth to Cerberus, Orthrus, the Chimera, the Nemean lion, the Sphinx and the Hydra. (Other ancient authors, such as Hyginus, attribute even more monsters as children of Echidna such as the Caucasian eagle, the Crommyonian Sow, the Colchian dragon, the Harpies and Scylla.) Drakaina (mythology) In Greek mythology, a drakaina () is a female serpent or dragon, sometimes with humanlike features.