''Arthanareeswara'' (half-man and half-woman) temple, dedicated to God Shiva and Goddess Parvati, Tiruchengode, Tamil Nadu

Ardhanareeswarar_temple, Tiruchengode en.wikipedia.org

Ardhanareeswarar_temple, Tiruchengodee, Mandabam (hall) en  wikipedia.org
Arthanareeswara temple, an ancient Hindu temple, in Tiruchengode, Namakkal district of Tamil Nadu,  is dedicated to a unique god of Shiva who is  half-male and  half-female, symbolic of gender equality. It is a rare  form of god  in the Hindu pantheon enshrined as the principal deity. Tiruchengode, one of the most important pilgrimage centres in South India,  has as many as
108 Theerthangal or water bodies  and among them, the most important one is Ammaiappar Thertham  at  the feet of Lord Arthanareeswarar templeIn the ancient work of Silapathikaram the place is mentioned as  'Neduvelkundru'. Muttuswami Dīkshitar, a famous trinity of Carnatic music, wrote compositions in praise of  Arthanāreeshwaram.  Tamil sant Sambandar composed the Tiruneelakanda Pathigam here, to help devotees get rid  of ailment.  Saint Arunagirinathar also composed ''Thirupugazh'' on Lord Subramanya here on the hill.

The deity here is also known as Madhorubagan and Ammaiyappan (mother-father). The famous Chenkottu Velavar Temple, dedicated to Lord Murugan, is also situated on the same hill
Way to the hill top, Ardhanareeswarar_temple, Tiruchengodeen..arthanareeswarar.com
Atop the sacred  hill (about 650 ft. high and a climb of 1156 steps; total height of the hill is 2000 ft from msl, covering 350 acres), the temple is dedicated to Ardhanareeswarar, a foot tall idol  and  Lord Shiva is known as Maathoru Paagar and the Ambal, his consort, is known as Baagampiriyaal Ammai.  Though sanctum- garbagriha  faces the West, the main entrance to the temple is in the South. The compound wall of the temple  has a length of  260 feet from east to west and 170 feet from  north to south and height of 16 feet. The main tower (84.5 ft tall gopuram) has 5 tiers on the north side and   is called Thirumalai Gopuram  built by Sri Krishna Devarayar in 1512 and the basement (kalkarar) was built during the reign of Sadasiva Maharayar.
Ardhanareeswarar_temple, Tiruchengode  epuja.co.in
 There is a Subramanya (Karthikaya) shrine on the back of the sanctum known as Chengottu Velar on a flat part of the  hill top.  Almost every famous temple has a water tank and the one  here is called   Sangu Theertham.  There is a natural water spring at the foot of the image, which is believed  to have been divinely  formed - a sort of   Navabashana type (“Uli Padaa Uruvam”) sculptured without tools'.  For the convenience of devotees who physically  climb the tall hill,  many mandapams (small halls) are built on the way where  people  can relax for a while and resume their journey uphill. There are 11 mandapams meant for shelter of pilgrims to this holy hill-shrine.  Along the path are 60 steps known as  the Arubadam Padi (Aarupatham Padt in Tamil)), that are  considered as holy and are  are mentioned by Arunagirināthar, a great Tamil saint. The hall right in front of the Chengottu Velar shrine has many nicely carved sculptures  with complex, intricate designs. At this temple,  among the six-time puja (Aarukala puja), the “Artha Jaama Pooja" - the late night worship service is believed to be  significant. Also considered to be special are the New moon days
Ganesa temple (Ucchi pilliyar kovil), Tiruchengode .youtube.com/
God Ganesa's shrine (Ucchi Pillaiyar shrine)  is  further up on the hill (425 feet further up).  An interesting feature is the presence of two big pieces of  rocks called Varadikal, Maladi kal, or Vandhya Paatana Sikara. Normally, childless couples  never fail to pray at this shrine to be blessed with a baby.   That a stone-carved image of a British colonial officer, Davis, in the Mukkoottu Vinayagar temple is a mystery.
Lcation map, Tiruchengode. TN .shivatemples.com
The annual chariot festival,  a 15-day event, of the Sengottuvelavar  held in the month of Vaikāsi gets a huge crowd.  There are 
four separate historical chariots that  carry the utchavar deities through the streets. They  include Lord Ganesha, Sengottuvelavar (Murugan),  Arthanāreeshwara and the last one  Adikeshava Perumāl (Vishnu). The largest chariot being that of  Arthanāreeshwara  donated to the temple by Nagamalai Gouder in 1699;  the chariot of Sengothuvevar was donated by Chennaraja Chikendar in 1628 and the  rest  two were made by Kondabhupathi, the ruler of Kongunādu, in 1628.

According to the Hindu mythology it was Adi Kesava Perumal, a form of Vishnu enshrined here, instructed Gowri  to perform the Kedara Gowri Vratam. The Goddess did this vratam (austerity) and united with  Shiva as Ardhanareeswarar, an embodiment of male-female equality, implying Shiva can not function alone without Sakhti (goddess).   Once on a visit to Kailash  Lord Vishnu, Lord Brahma, Indra and sage Birungi first worshiped Parvati (Shiva's consort) except sage Birungi, who tried to see Lord Shiva first. Parvathi Devi, who became furious stopped the sage to proceed further. Lord Shiva  blessed Birungi with a third leg which enabled the sage to get blessed by the lord. Realizing her mistake, Parvati wanted to placate  Shiva and with lord's approval, did penance on a hilltop. On completion of this penance, Goddess Parvati  demanded  a portion for her in Lord Shiva's sacred body so that she  could bless the devotees along with the lord. This  manifestation of half man (right side) and half woman (left side)- Arthanaareswarar personifies simultaneous worship of both Parvati and Shiva in one idol. In reality, it implies the creation of living things. 
Stone-carved serpent,, Ardhanareeswarar_temple .tamilbrahmins.com
Yet another mythology points how the word Chengode came into being. In the battle between  Adiseshan (serpent)  and Vayu (wind) to prove their prowess, finally Adiseshan clung to Mount Meru with his hood and Vayu had  to release him with his power. Infuriated Vayu stopped the air and this resulted in living being facing near death. When Vayu suddenly released the air, the top of the mountain with the head of Adisesha, thrown into the earth  at three places with flesh and blood, making it red and thus the name Chengodu  was born . Surprisingly, there is a 60 ft long snake carved on the hill, and hence the name as Nagamalai (in Tamil Naga means serpent and Malai means hill).  The hill is known as 'Nagagiri' in the Thevaram hymns.  Chola, Pandya and Nayak kings of Tamil Desam made valid contribution to this temple.

Another fascinating feature of this holy place is  performing ''Girivalam'' -  the practice of  going around the holy hill barefoot  clock-wise. It is done on the  full-moon days by a huge crowd and it is a 7 km stretch to complete the circle. Generally,  it might take  about 1.5 hours to cover the distance. Women and children also participate in this ritual as part of their prayer.