This small site is worth a stop for its intriguing House of the Tiles, one of the most important Greek remains from the 3rd millennium BC. It's very well preserved, conserving the base of staircases as well as plaster on the brick structure. Clay seals found here attest to a system of control over goods. Other remains include walls and a tower from earlier in the Helladic period, as well as later Mycenaean tombs. It's 7km west of Nafplio along the coast.
Lerna is also famous in mythology as the lair of the Hydra, which was slain by Hercules as one of his labours.