The Arunachaleshwar temple at Tiruvannamalai is one of the holiest Saivite shrines in the country. Lord Shiva is worshipped here in the form of Arunachaleshwarar, also known as Annamalaiyar. The temple is one of the Panchabootha stalas (temples associated with the five basic elements – water, wind, fire, sky and earth) and is associated with Agni or Fire.

The temple is located at the foot of the Mount Arunachala (Aruna – red + Achala – immovable mount). The mountain is believed to be sacred and hence, many saints and siddhas have made it their home.

Thousands of devotees circumbulate (pradakshina) the mountain (also known as Girivalam) on full-moon days and also during certain festivals. The deepam festival during the month of kartigai is celebrated with great fervour. A big brass lamp is lit at the peak of the hill. The blazing flame atop the hill is witnessed by millions.

The mount is considered by some to be the physical embodiment of Lord Shiva himself. Legend has it that once, Lord Vishnu and Lord Brahma quarrelled to ascertain the superiority of one over the other. They sought the help of Lord Shiva to judge as to who was really superior. Lord Shiva transformed himself into a flame of light and asked them to find the root and the crown. Both of them failed. They requested Lord Shiva to moderate His appearance. Lord Shiva obliged and manifested Himself as the sacred Mount Arunachala.

The sacred mountain was covered with dense forests in ancient times. Increasing human pressure resulted in almost complete loss of the forests. The mountains became dry and hot, with few plant and animals. But, in recent years, afforestation programmes have been initiated in the hill, especially along the pilgrim tracks.