Annamalaiyar Temple is a Hindu temple dedicated to the deity Shiva, located at the base of Annamalai hills in the town of Thiruvannamalai in Tamil Nadu, India. The temple at Tiruvannamalai is one of the biggest and grandest temples in South India. With the hill as back ground it gives the appearance of a fort to those who see it from a distance. The temple complex covers 10 hectares, and is one of the largest in India. It houses four gateway towers known as gopurams. The tallest is the eastern tower, with 11 stories and a height of 66 metres, making it one of the tallest temple towers in India. The temple has numerous shrines, with those of Annamalaiyar and Unnamulai Amman being the most prominent. The temple complex houses many halls; the most notable is the thousand-pillared hall built during the Vijayanagar period. The history of this Annamalayar temple dates back to thousand years. Mention has been made in the Thevaram and Thiruvasagam, both great works in Tamil. The Karthigai Deepam festival is celebrated during the day of the full moon between November and December, and a huge beacon is lit atop the hill. It can be seen from miles around, and symbolizes the Shiva lingam of fire joining the sky. The event is witnessed by three million pilgrims. On the day preceding each full moon, pilgrims circumnavigate the temple base and the Annamalai hills in a worship called Girivalam, a practice carried out by one million pilgrims yearly.