Vishnu is known as the great preserver and of all forms of life.

Once during Samudra Manthan of the great churning of the seas by the gods and the demons, Vishnu decided to change himself into a tortoise and help in this mammoth task.

The churning was to bring out the potent drink amrita from the depths of the ocean to help regain power and immortality.

The huge mountain, Mandara, was used as the pole for churning the water. But as the churning continued, the mountain began descending into the sea.

The worried gods then prayed to Vishnu, who changed himself into a huge tortoise and placed the mountain on his back.

The churning began and this time it continued smoothly.