What is "akshayavat"

Akshayavat or Akshay Vat ("the indestructible banyan tree") is a sacred fig tree mentioned in the Hindu mythology.

According to a legend, once the sage Markandeya asked Lord Narayana to show him a specimen of the divine power. Narayana flooded the entire world for a moment, during which only the Akshayavat could be seen above the water level.