Karthigai Deepam is a Hindu festival celebrated primarily in the southern states of India, particularly Tamil Nadu. It usually falls in the month of November or December, during the full moon of the Karthigai month in the Tamil calendar. The festival is marked by the lighting of oil lamps, symbolizing the victory of light over darkness and knowledge over ignorance. The highlight of Karthigai Deepam is the grand lighting of a massive beacon lamp on the hilltop of Thiruvannamalai, which represents the divine light of Lord Shiva. Devotees gather to offer prayers, light lamps at their homes, and participate in various rituals, fostering a sense of community and spirituality.