Sri Sankaranarayana temple in Sankarankovil, Tamil Nadu - a temple of great antiquity

Sankaranarayanar koil, Sankarankoil,en.wikipedia.org
Sri Sankaranarayana temple in Sankarankovil, Tirunelveli district is a  large Hindu temple  and the presiding deity is Sankaranarayana -half Vishnu and half Shiva.  Once upon a time, the ignorant devotees of Lord Hari (or Vishnu) and Lord Shiva, not knowing both gods are one, had a heated debate on  as to who was more powerful than the other. The discussion continued unabated  and this confused other devotees who worshipped both gods. With no recourse available, both Gods Shiva and Vishnu  appeared as Sankaranarayanar to  tear off their veil of  ignorance and idiocy and to impress on them that both Hari and Shiva are one and the same. The question of superiority or inferiority does not exist among the Gods and goddesses and only the narrow-minded humans draw a line between the Gods.
Sankaranarayanar koil, Sankarankoisankarankovil temple.tnhrce.in
This temple was built in the 11th century AD by king Ukkira Pandiyan who ruled over Ukkirankottai. The legend has it  once Punnai forest was taken care of  by one  "Manikkeerivan", a Devan (celestial) who was cursed by Goddess Parvathi, consort of Shiva to tend the forest here. 

One day while he was clearing the bushes, etc he saw a snake in  a pit with its tail cut. Besides he also saw a  Sivalingam close to the snake. Suspecting divinity in that place, Manikkeerivan informed about this to king Ukkira Pandiyan who happened to pass through the forest. The ruler  also suspected divinity in that place and made a decision to have a temple  built in that area with a temple tank, halls (mandapams), etc. 
Sankaranarayanar koil, Sankarankoil sankarankovil temple.tnhrce.in
The huge entrance tower (Rajagopuram)  with  9 tiers  was built by  Seevalaramapandian in the 12 th Century.  He also built the front mantapam. There is a separate shrine for Vinayaka who is referred to as  Anugnai Vinayaka. The deities of this temple are Sri Sankareswarar, Sri Gomathi Amman and Sri Sankara Narayanar. It is said it was Uma Devi who requested lord Shiva to prove the people that both Shiva and Vishnu are actually one god.
God Shankaralingam  Sankaranar kovil. Dinamalar Temple
The ant-hill ( in local parlance ''puttumann'' ) soil, found in the Amman shrine,  is believed to have medicinal properties and is offered as Prasad to the devotees.  People who consume it with water  report improvements in their ailment.  Devotees in this temple offer  silver pieces embossed with the images of such creatures s snakes, scorpion, etc to ward off their problems. It may be superstitious, but people do find relief.

The snake pit (Ant Hill) is called "Vanmeekam" (Tamil:). Hence the deity Sri Sankaralingar is also called "Vanmeeganadhar"
The Nithya Annadhanam is being conducted in the temple  to feed around  100 devotees. Navarathri, Thiruvenpavai and Shivaratri are major festivals here.  Sankarankoil is  30 km from Rajapalayam and 56 km from Tirunelveli. Bus and rail facilities are available from Madurai.Lord

http://sankarankoviltemple.tnhrce.in/deites.html https://en.wikipedia.org/wiki/Sankaranayinarkoil