Nedungadu is a place with historical and archeological significance. It is 10 km north-west of Karaikal
Among the highlight is Sri Tantonreeswarar Temple, a shrine dedicated to Lord Shiva. It was declared a protected monument in 1971.
Several bronze images have been discovered from this place, and most important of these are the idols of Pillaiyar, Manickavasagar, Thiru Gnanasambandar, Skandan, Uma, Jnanasakti (a pair), and Sivakamasundari. Also excavated are trident, conche, copper tripod, plate and a pair of sandals.
A major draw is the annual festival held at Sri Mariamman temple.