The Grand Anicut is known as the Kallanai meaning STONE DAM in Tamil Nadu, India, which is the ancient stone dam built on the River Cauveri in the state of Tamil Nadu of south of India. This Ancient Stone Dam was built by King Karikalan of Chola kingdom. It was proved that the dam built around first Century (1 AD). Made of unhewn stones, the Kallanai dam is 1080-foot long (329 meters) and 60-foot wide (20 meters) across the main stream of the Cauvery.
The dam is considered OLDEST not only for strorage but also the oldest water-diversion cum water-regulator structure in the world which is under good service http://www.heritagetown.org/video/video.html