Karthigai Deepam is the most important and famous festival of Tiruvannamalai.Celebrated during the Tamil month of Karthigai.The festival traditionally extends over several days.The grand Mahadeepam is lit on the summit of Arunachala Hill.The enormous flame represents Lord Shiva as the infinite column of fire (Jyoti).Large numbers of devotees gather for the festival and perform Girivalam around Arunachala Hill.