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
Greek ironclad Hydra Greek ironclad Hydra Hydra () was an ironclad warship of the Greek Navy, named for Hydra, one of the Saronic Gulf islands which played a key role in the war at sea during the Greek War of Independence. The lead ship of her class of ironclads, she was ordered in 1885 in response to a crisis in the Balkans and Ottoman naval expansion. The ship was launched in 1889 and delivered to Greece by 1892. She was armed with a main battery of three guns and five guns, and had a top speed of . "Hydra" and her sisters saw