What you have show in below picture may not be correct compared to the photo i have seen at Gokarna/. The complete story is here
I found the story very fascinating, click on the link above and do read it.
Gokarna, a famous Shiva temple. In the Puranas, it says that Ravana was carrying a Shiva Linga given to him by the Lord himself from Mount Kailas to his home in Lanka. The Shiva Linga was very heavy. In fact, Shiva had warned Ravana that once he put it down he would not be able to lift it again. However, Lord Ganesha knew that if the Shiva Linga were to leave India, the country's prosperity would be adversely affected. Thus he devised a trick, through which he was able to make the Shiva Linga touch the ground in Gokarna. Ravana tried with all his might to lift the Shiva Linga, but he could not. He was furious, and in his final attempt to lift it, the Shiva Linga broke into six pieces. The main piece stayed stuck to the ground in Gokarna, and Gokarna Shiva Temple was built around it. The other five pieces landed in Shijeshwar, Siddheshwar, Murudeshawar, Gunavantheshwar and Dhareshwar.