"Maha-Sivaratri" is a Hindu festival observed on the night of the fourteenth day of the dark half in the month of 'Magha', in Tamil 'Thai', corresponding to the English months 'February - March', in honour of Siva
The Lord Mahavishnu, one of the Hindu Trinity, representing the preservative aspect of the universe as in his previous incarnations (avatars), descended into the world to kill the ten-headed Asura named Ravana..
Panguni Uttiram is a festival celebrating celestial marriages. Lord Shiva weds goddess Meenakshi (a Parvati incarnation) on this date. Also celebrated is the marriage of Lord Subramanya to Theivanai, the adopted daughter of Indra.