The Mangaladevi Temple, located within the Periyar Tiger Reserve in Idukki, Kerala, opens to devotees once a year for the Chitra Pournami celebrations in April or May. This 1,000-year-old temple, built from granite and situated at an altitude of 1,337 meters, honors the deity Mangaladevi, also known as Kannaki.

Mangaladevi, the heroine of the Tamil epic Silapathikaram, symbolizes moral power and justice. The temple was established by the ancient Tamil king Cheran Chenguttuvan in her honor, commemorating her legendary act of burning the city of Madurai to avenge her husband's wrongful death.

The Chitra Pournami festival, celebrated on a full moon day in the Tamil month of Chithirai, draws numerous devotees from Kerala and Tamil Nadu. The festival features ritualistic prayers and poojas conducted by priests from both states. Women devotees participate in large numbers, cooking and offering Pongal, a sweet rice dish, to the goddess. The main deity, decorated with flowers and silk, is the focal point of the rituals, which are believed to bless women with long and happy marriages.

The pilgrimage to Mangaladevi Temple is a significant aspect of the festival. Devotees embark on a 12-kilometer trek through dense forests and grasslands, starting from the Periyar Tiger Reserve. The trek is accessible only by jeep, and the district administrations of Idukki and Theni ensure that the pilgrimage does not disturb the local ecosystem. Forest officials maintain a constant vigil to protect the area's rich biodiversity, which includes the endangered Nilgiri Tahr and various orchid species.

The temple's architecture reflects Pandyan influences, with four stone structures housing various idols. Despite its dilapidated condition, the boundary walls and steps made from huge stones bear testimony to its historical grandeur. The temple complex features sculptures and engravings related to Silapathikaram. Visitors are greeted by a statue of Karuppa Swamy at the entrance, alongside a dilapidated Shiva temple and a sanctorum for Lord Ganapathy.

The forest department takes various measures to safeguard the ecosystem, including restricting the number of visitors and ensuring that the surroundings are not disturbed. The trek to the temple offers breathtaking views of the Western Ghats and the lush greenery of the Periyar Tiger Reserve, making it a serene and spiritually enriching experience.

The Chitra Pournami festival at Mangaladevi Temple is a unique blend of history, mythology, and natural beauty. It provides a rare opportunity for devotees to connect with the divine in a pristine, untouched environment while also celebrating the enduring legacy of Kannaki, a symbol of justice and moral strength.