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
Hydra (Within Temptation album) made the cover for "The Unforgiving". The album title refers to the great variation in musical genres the band improves on with each new release. About the concept, guitarist Robert Westerholt says: ""Hydra" is a perfect title for our new album, because like the monster itself, the record represents the many different sides of our music." According to the ancient Greek mythology, the Hydra was a giant multi-headed serpent that, for each severed head, sprang forth two more in their place. As the title, the sound composition of the album was said to be varied, as Westerholt said, also referring