The temple of with its soaring shikhara dominates the skyline and life of Ujjain. The God Shiva reigns eternal and the lingam, one of the 12 jyotirlingams in India, is believed to be swayambhu (born of itself), deriving its shakti or power, from within itself.  
The idol of  Shiva is consecrated in the sanctum above the Mahakal shrine and the images of Lord Ganesh, Parvati and Kartikeya are in the west, north and east of the sanctum sanctorum. To the south is Shiva's bull steed, Nandi. This temple has five levels, four above ground and one underground which is lit by brass lamps to light the way. 
 

According to Shiva Purana, when Shri Ganesh was married of before Kartikeya, and because of this Kartikeya became angry, and despite being stopped and consoled by his parents Shiv-Parvati, went away to the Kraunch Mountain. Even the Gods went and tried consoling Kartikeya, but all their efforts were in vain, because of all this Shiv-Parvati were very sad and both decided that they would to Kraunch mountain themselves. When Kartikeya came to know that his mother-father have arrived he went away. Eventually Lord Shiva assumed the form of Jyotirlinga and resided on that mountain by the name of Mallikarjuna. Mallika means Parvati, while Arjuna is another name of Shiva. In this way both Shiva and Parvati reside in this linga. The people who visit this Jyotirlinga are emancipated from all their sins and fulfill all their desires. It is for the welfare and well being of one and all.