Mangaladevi Kannagi Temple is an ancient, historic temple situated at the border between Theni in Tamil Nadu and Idukki in Kerala. It is situated deep inside the forest of Periyar Tiger Reserve. The temple is believed to be more than 1000 years old. This is the place where Kannaki, a legendary Tamil woman transformed herself into the divine Mangaladevi. Kannaki was the wife of Kovalan. Kovalan was killed after being falsely accused of robbery. To avenge the wrong punishment, Kannaki burned the whole of Madurai and came to Suruli hills. It is believed that she went to heaven in the Pushpaka Vimana with Kovalan from more there. Inspired by this story, Chera Chenguttavan, the King, erected the temple of Mangaladevi here. It is situated at a height of 1337 m. above sea level. Chenguttavan narrated the story of Kannaki to the Tamil post Illango Adigal and he wrote the famous “Silappathikaram” based on the story. The temple is famous for its Pandyan architecture. The boundary walls and the steps to the temple are made of huge stones. One can only marvel at the effort required to take these to the top of the hill where the temple is situated. Apart from the idol of Mangaladevi, there are those of Karuppuswamy, Lord Siva and Ganapathy also consecrated here. There is an underground passage that is believed to lead to Madurai. The temple is open for worship only on one day in a year. It is on the day of Chithra Pournami, the full moon day in the month of Chaithra (April/ May) Pujaris from Tamil Nadu and Kerala perform the pujas on that day. As the temple is on the verge of ruin, the Panchaloha idol for the festival is brought from Kambam. On that day the Goddess is decorated with flowers and silks and poojas are offered. Women also offer Pongala on that day.  Devotees can go to the temple only with prior permission from the Wildlife Warden at Idukki. The 12-kilometer journey to reach the temple is through dense forests and grasslands.