Thillai Nataraja Temple:

Thillai Nataraja temple located in Chidambaram. It is also called as Chidambaram Temple. This temple is dedicated to lord Shiva. It is one of the five Pancha Bootha Sthalams the devotional shiva temples each represented by five elements. The temple is known for its mystery as Chidambara Rahasyam (secret). The priest who performs all the worships for the day leaves a curtain. The people are stood on the other side of the curtain. After this at a particular time each door of the main temple is opened and lord Shiva is worshiped. It is believed that lord Shiva himself in the form of nataraja appears to some people while this ritual is done on the other side of the curtain. This appearance of Lord Shiva in the form of nataraja is said to be mysterious about this temple. More about chidambara rahasyam can be learnt here: Reference: http://www.chidambaramnataraja.org/rahasyam.html