From PhalkeFactory

Only some places retain a special charge, the way Trybakeshvar. The demons and the gods were exhausted. Time was being swallowed up, seasons passing as they continued pulling the mountain, Meru between them by a large green rope around it. They were trying to make a churn of the mountain, to make the ocean yield up its treasures. The 'rope' was the giant snake Vasuki whose skin was red hot from the exertion, whose eyes bulged with veins so thick and red that the first Asura who held the head, never dared look down at what he was holding.

Samudra manthan.jpg

All manners of gems were thrown up from the waters, into the skies.. Kamadhenu of the soft black lidded eyes, the cow that gave all, a white horse that could fly.. the sky was resplendent with her new constellations but for the gods, they were still searching for the elusive amruta, which once tasted, would keep the scythe of death away, forever. Still new to life, they had experienced, in their battles, the ogre of death, they wanted to defeat him and play and fight eternally.

a few drops of the Amruta when it finally appeared fell, in the machinations, the fights, the interventions that were made to distribute it. The drops fell on some places on earth.. one of those places was Trymbakeshwar.