Banasura Sagar dam is the largest earth dam in India and the second largest of its kind in Asia. The dam is made up of massive stacks of stones and boulders.Situated about 15 km from Kalpetta, the dam holds a large expanse of water and its picturesque beauty is enhanced by the chain of mountains seen on the backdrop. It is constructed in the Banasura Lake and the nearby mountains are known as Banasura Hills. Legends say that the Asura king of Banasura, (the son of King Mahabali, who is believed to visit Kerala during every Onam festival) undertook a severe penance on the top of these hills and thus it was named after him. The scenic mountains beckon adventure tourists and the dam site is an ideal starting point for trekking.