Today we celebrated the Karthigai festival. Its a festival of warmth, lamps, and light. Its a time to meet the family, spread the cheer, and generally be happy. To mark this occasion the following extract from Tamil Nadu tourism website is replicated here for people to understand the significance.

From tamil nadu tourism:

There is an interesting story explaining the link between Karthigai and lamps. Legend has it that Lord Vishnu and Lord Brahma began to quarrel as to who was the more powerful of the two. While they were fighting, Lord Shiva appeared before them in the form of a huge pillar of fire. Lord Vishnu and Lord Brahma gave up quarrelling and decided to find the top and the bottom of the pillar.

Accordingly, Brahma assumed the form of a swan and moved upwards. Vishnu transformed himself into a boar and started digging deep into the earth. But even after searching for several years, neither of the two was able to find the ends the pillar. Finally, they realised that the pillar was none other than Lord Shiva.
Soon afterwards, Lord Shiva appeared as a hill (Arunachala Hill) at Tiruvannamalai in Tamil Nadu. Indeed, the very names `Tiruvannamalai’ and `Arunachala’ translate as `holy fire hill.’ The Shivalinga in the temple here is the agni linga. The tiny lamps lit during the Karthigai festival (Karthigai Deepam) are believed to be the miniature replicas of the fire linga. Every year thousands of devotees from Chennai and elsewhere flock to Tiruvannamalai to see the spectacular Karthigai Deepam there.