The Kalpabata or the big banyan tree is said to have existed
Kalpataru – Kalpabriksha – Kalapabata
since long. this tree Kalapa Bata finds mentions in Skanda Purana and Brahma Purana. Skanda Purana says that in the beginning of the present Kalapa ( the span of time between two deluges) Bishnu and Laxmi were in this Pursottam Khetra floating in the water. At that time a sage Markandeya, who supposed to live for seven Kalpas, was also floating and he was also searching for a shelter. He could find the banyan tree and came near to it., till he heard the voice of a child, which directed to him closer. He saw Bishnu and Laxmi. Bishnu instructed him to limb up the tree and enter the mouth of the child. Markandeya did accordingly and saw the entire universe in the abdomen of the child. Later Bishnu advised him to dig a pond for him at north-west side of the tree.
Around the holy tree Kalpabata, devotee find the temples of Bateswara, Batakrushna, Balamukunda, Bata Mangala, Bata Narayan, Bata Ganesha, RadhaKrushna, Bata Jagananth, Panchu Pandab and Mahadev.
Virtue of Kalpabata Tree is described in many Hindu Spiritual Mythology like Sknada Purana, Brhma Purana, Tirtha Chintamani, Bhagabata Mahapurna, HariBansh, Bhabishyaparba, Pramabhakti, Brhmagita, Chandrakala, Rasika Harabali, Saragupta Gita, Tulabhina and Astagujari.
Skanda Purana also depicts that Sabara King Biswabashu was worshiping Nilamadhab under this tree. The Kalpa Brukshya is also found mention in Brahna Purana that say it was never destroyed even after the end of Kalpa. The Pilgrims and visitors circumambulate the tree along the narrow passage and it believed that the tree divine power of wish fulfilling.