Name : Thalamalai Sanjeevi Perumal Temple aka.,Nallendra Perumal Temple
Location :
At a distance of 5 km from Sevinthipatti, 39 km from Gunaseelam, 34 km 
from Namakkal, 95 km from Erode, 65 km from Trichy & 354 km from 
Chennai, the ancient and famous Thalamalai Perumal Temple is situated on
 a unique rock on the peak of Thalaimalai Hill. It is a renowned 
Vaishnava temple.
Legend :
1. In Ramayana, great of the two great epics of Hindu mythology, Lord Rama 
on his way back to Ayodhya with Sita after rescuing her from Ravana in 
Lankan lands, he had to stay at this Sthala, a spring by name Ramar 
Sunai was made and there is water flow always. When a person goes close 
this spring, he can breathe the pleasurable smell of turmeric.
2. In Ramayana, the  Yuddha Kanda, Indrajit, son of Ravana and the primary
 of army of demons showered deadly weapons (the Brahmastra.) to kill his
 enemies - Rama, Lakhmana and vanaras and they were unconscious. 
Jambavan sent Hanuman to fetch the Sanjivi, a powerful life-restoring 
herb to revive the unconscious. Unable to find the specific herb before 
nightfall, Hanuman brought the entire mountain Dronagiri which was full 
of medicinal plants, to the fight field, thus helping find the herb and 
even with the approach of the Sanjivi hill, (fragrance of the herbs) 
Rama and Lakshmana and the Vanaras felt the darts slip off their bodies.
 Their wounds healed. Jambavan told Hanuman to replace the Sanjivi Hill 
but Hanuman was tired to go back to the spot and he tied the hill in his
 tail and threw it with full vigour. The top portion of the hill fell 
and that place came to be known as Thalaimalai.
Description :
 The temple is open only in the Tamil month of “Puratasi” (Mid of 
September to Mid of October). During this period, people from 
surrounding areas would come to this temple and worship. The temple is  atop nearly 2300 Feet above sea level.
This hill gets its name because it resembles the head of a person. This 
hill is also known as Siragiri.
The presiding deity of the temple is 
Nallendra Perumal, a form of Lord Vishnu. One can find shrines of 
Venkatachalapathy, Alamelu Mangai Thayaar, Goddess Mahalaxmi, Sri Devi, 
Bhudevi, Lord Anjaneya, Garudazhvar, and Karupanna Swami. If one takes a
 holy dip in the Kannimar Sunai and pray to Lord Nallendra Perumal, they
 would be void of the bad effects of Lord Shaneeswar. This temple was 
built by Madurai Nayaks.
There is a spring called Ramar Sunai 
with water flowing all the time. 
Visitors need to trek for about 4 kms through rocky 
path running through steep stretches at times. It usually takes about 2 
hours to trek upwards. The trekking starts from Thalamalai foothill, 
which is about 10 kms from Appananallur. From Trichy, the route goes 
through Guanseelam, Musiri, Manamedu and Appananallur.
Devotees walk around on a narrow path 
around the temple for pradakshinas. People strongly believe that going 
round this rock temple would give them successful marriage, wealth and 
child birth. Doing this ritual is now banned after an accident.
One can find Sanjivi herb spread in this hill and the pilgrims who 
workshopped this temple would be guarded against the sting of poisonous 
insects and snakes. There is no threatening to their lives.
Festivals :
Annual festival is celebrated in Tamil month of Puratasi (September / 
October), once in three years poojas for Edi Bhagavan (Thunder) are 
performed here.
Timings: 6 AM to 9 PM on Monday to Saturday and 6 AM to 2 PM on Sunday
Websites :
http://www.gconnect.in/guestarticles/thalaimalai-hills-unseen-serene-beauty-of-nature.html
http://amudhasurabi.com/tour/Trichy/ThalamalaiTemple
https://www.trawell.in/tamilnadu/tiruchirappalli/thalamalai-perumal-temple