The coming together, union of Shiva and Parvati is celebrated as Shivaratri. During the dance of Shiva, Tandava Nritya with the Damaru, there is no other sound except the sound of the Damaru. Yogis who meditate and go deep, will first hear the heart beat sounding like a Damaru. Shiva is dancing the dance of destruction, so is it destruction? It is not. It is regeneration. Because if the old is not destroyed, there is no space for the new in this world. If ignorance is not destroyed, there is no place for knowledge in this world. Therefore the Tandava Nritya, where everything shakes, is a demolition, so that new things come.
