There are 6 special temples in Tamil Nadu, dedicated to the god Murugan, mostly referred as the Tamil God and as the god of the mountains/hills. These 6 temples are known as Arupadai Veedu (The Six Warhouses -The Six Abodes of Murugan), very important in the hindu sect Kaumaram (the sect that worship lord Murugan only). Lord Murugan is usually referred as the son of lord Shiva. The six places are important places, and takes part in the Skanda Purana (and other tamil litteratures), that describes the story of Murugan, and how he fought against the demon, Surapadman and other important incidences.
The places/temples are listed by sequences in the story, Skanda Purana:
Thiruthani, known as Thiruthanigai in earlier times, is located 87 km from Chennai, on the hill Thanigai. Thiruthani is actually the 5th of Arupadai Veedu of the lord Murugan, but was the first Arupadai Veedu, that we visited. It is also the first tempe we went to outside Chennai (except Mahabalipuram, which is more a tourist place now than an actual temple). From here, we went to Srikalahasthi.
Thiruthani is known as the place, where Murugan married Valli, and he eventually met her in a place nearby. This was also the place, where he took rest and gained inner peace after defeated the demon, Surapadman. This hill/temple has 365 steps, referring to the 365 days of a year. Thiruthani is mentioned in one of the earliest tamil sangam literature, Thirumurugaatrupadai, written by Nakkeerar.