Shiva Lingam is the symbol of Lord Shiva. Shiva lingam has been propitiated by great sages and puranic men from ages. Many of them believe that Shiva Linga is the genital organ of Lord Shiva and the platform on which it is installed the female genitalia or the yoni of Mother Parvathi. The concept of phallicism entered in to the worship of Shiva Linga by foreign scholars who researched on Hinduism and the philosophies of the holy trinity namely Brahma, Vishnu and Maheswara. Generally Shivalinga is explained in another way. In a typical shivalinga Lord Brahma represents the pedestal, Lord Vishnu represents the platform and the egg shaped structure represents Lord Shiva, together constitutes the birth and ending of universe.
There are many stories surrounding this concept but there is a different meaning for Shiva Linga. Mark is the meaning of linga in sanskrit. Now Shiva linga means the mark of god which resembles the very creation. There were two types of lingas which are made from an egg like stone and another from solidified mercury. The egg shaped linga represents the cosmic egg or the source of universal energy. Comparison with the male genitalia came in the middle when the world started looking at all sexual activities in the aspect of divinity.