The Mariamman Theppakulam is a huge tank which is 1000 feet long and 950 feet wide. In the center of this tank there is a mandapam cum Lord vigneshwara temple. During festival season, this tank is filled with water and decorated with lights . This float festival is celebrated here on the Full moon day in the midst of january and febrary The tank turns colourful, which attracts the eyes of the visitors. The tank originated when the Earth was dug to build Thirumalai Nayakar Mahal. But due to some reason this project was been failed. And so this place was converted as Theppakulam. Now-a-days people started going for walking around this tank. The area of the tank and the island pavilion with a garden in the center is approximately equal to the area of Meenakshi Temple. Huge trees with Nagalingam flowers can be found here. The tank is connected to river Vaigai through underground channels. The tank has total of 12 long stairs (steps) on all four sides.