Arudra Darisanam or Arudra Darshan takes place on full moon (along with Arudra Birth Star) in the Tamil month of Margazhi (Dec-Jan).It is the longest night in a year. It celebrates the cosmic dance of Lord Shiva as Nataraja. Special pujas and rituals are held on the day at the temple. Legend has it that Lord Shiva performed the cosmic dance in the form of Nataraja at Chidambaram for his devotees Adi Shesha and Vyagrapaadar. Adishesha(the seven-hooded serpent on whom Lord Vishnu rests) and Vyagrapaadar was a devotee of Shiva. Both yearned to witness the Ananda Tandava of Lord Shiva who granted their request and performed it at Chidambaram.The cosmic dance of Lord Shiva symbolizes pancha kritya (five divine acts) of creation, sustenance, dissolution, concealment and bestowing of grace.