Arunachalam in Tiruvannamalai is primarily known for the Arunachaleswarar Temple, a large and ancient temple dedicated to Lord Shiva, who is worshipped here as Arunachaleswarar or Annamalaiyar. This temple is famous as one of the Pancha Bhoota Sthalams representing the element of fire (Agni). Lord Shiva is believed to have manifested here as a massive column of fire, and the temple complex is renowned for its grandeur, spiritual significance, and festivals.

The temple dates back many centuries and has contributions from the Chola, Vijayanagara, and other dynasties. It also has the second-highest gopuram (temple tower) in India, standing 217 feet tall. The sacred hill Arunachala behind the temple is itself considered a manifestation of Lord Shiva.