There are many legends about the Amarnath Cave and the yatra, and the most popular one being that Lord Shiva had to give in to his wife Parvati’s demands to tell her the secret of his immortality. But to ensure that no one eavesdrops, they set off for the mountain cave where he narrated the Amar Katha to her. His bull Nandi was left behind at Pahalgam, from where the Lord and his wife started their ascent. Today, it is a major starting point for the yatra.

The Shiv Lingam that people flock to see forms mysteriously and rises to its full growth on Purnima, night of the full moon. It is believed that this was the day when the Lord narrated the secrets to his divine consort.
The cave was discovered later (there are different legends associated with this discovery too), after which it became public knowledge and the annual pilgrimage started.