Banasura Sagar is the largest earthen dam in India and the second largest in Asia, built across the Karamanathodu river in 1979. The reservoir it creates has flooded a valley in the Western Ghats, leaving a series of small islands — forested hillocks rising from the water — that give the lake an attractive appearance. Boat rides between the islands are available from the dam site.
The dam is about 21km from Kalpetta, a straightforward drive through coffee estate country. The area is particularly atmospheric in the early morning when mist sits on the water. There are pedal boats and motorboats for hire at the jetty. The surrounding hills are good for short walks, and the whole area is quieter and less commercialized than many of Wayanad's other attractions.