This is the world's second and Asia's first arch dam, constructed across the Kuravan and Kurathi hills. 550 ft. high and 650 ft. wide, the dam lies close to the Cheruthoni barrage. The Dam was conceived by a superintendent of the Malankara Tea Estate who was on a hunting expedition and instantly recognized the potential of the place for power generation. Surprisingly, there is a famous legend associated with this dam as well. According to it, two natives were cursed by Lord Rama when he caught them staring at bathing Sita. The two natives, Koravan (man) and Kurathi (woman) who were converted into stones (on opposite banks of Periyar river) begged Lord Rama for mercy since they had never stayed separate. Lord Rama blessed them that they will stay together for years to come. And, today, the Idukki Arch Dam links the two hillocks, Koravan Mala and Kurathi Mala (thus in a sense reuniting them).