Omkareshwar (Hindi: ओंकारेश्वर Ōṃkārēśvar) is a Hindu temple dedicated to God Shiva. It is one of the 12 revered Jyotirlinga shrines of Shiva. It is on an island called Mandhata or Shivapuri in the Narmada river; the shape of the island is said to be like the Hindu ॐ symbol.
As per Shiv Mahapuran, once Brahma (the Hindu God of creation) and Vishnu (the Hindu God of Protection and Care) had an argument in terms of supremacy of creation. To test them, Shiva pierced the three worlds as a huge endless pillar of light, the jyotirlinga.
Vishnu and Brahma split their ways to downwards and upwards respectively to find the end of the light in either directions. Brahma lied that he found out the end, while Vishnu conceded his defeat.
Shiva appeared as a second pillar of light and cursed Brahma that he would have no place in ceremonies while Vishnu would be worshipped till the end of eternity. The jyotirlinga is the supreme partless reality, out of which Shiva partly appears. The jyothirlinga shrines, thus are places where Shiva appeared as a fiery column of light .
Hindu scriptures says that once upon a time there was a great war between Devas and Danavas(demon), in which Danavas won. This was a major setback for Devas and hence Devas prayed to Lord Shiva. Pleased with their prayer, Lord Shiva emerged in the form of Omkareshwar Jyotirlinga and defeated Danavas.
Mamleshwar Temple is located at Anuppur in Madhya Pradesh . This temple is dedicated to Lord Shiva and is one among 12 JyotirLinga.
The Omkareshawar temple is built in the North Inidan style of architecture, with high spires. Devotees consider worship to Panchamuga Ganesha, to be very auspicious. There is a shrine for Annapoorani. Siva Lingas of various sizes are sold in great numbers in this place.
It is said that once, sage Naradar during his visit to the Vindyas, sang the praise of mount Meru to Mount Vindhya. On hearing this, Mount Vindhya prayed to Lord Siva to gain in importance. Lord Siva blessed him & appeared here as Omkareshwarar & Amaleshwarar and gave the boon of grwoing, but without hindering Siva devotees.
But the Vindhyas did not stop growing, and even obstructed the sun and the moon. Sage Agasthyar subdued its growth by saying it should not grow till he gets back there. He never went back & hence the growth was arrested.
Omkareshwar is situated on the Mandhata hills in Madhya Pradesh, known in ancient times as Shivpuri. The temple dates back to the Krita Yuga. River Narmada flows here around the Mandhata hill in the form of an Om (Omkaram)