Nandi is a symbolism of Eternal waiting. In Hindu culture & tradition lord Shiva is the god of gods, the Rudra who gets angry very easily as he always remained in continuous meditative state. So to have an undisturbed meditation Lord Shiva had created several ganas among them the most prominent was Nandi a powerful humped bull. His duty was to guard the entry to kailash as a gatekeeper so that no one can disturb lord Shiva & also act as a messenger to lord. No one in this universe was allowed to disturb lord Shiva the only way to communicate to the lord was to whisper in the ears of Nandi who shall deliver it to the lord.

Story of gyanvapi.
Mahant Panna went to Nandi before jumping into the well, closed his eyes and started saying in his ear, ‘The calamity was also on Lord Rama, Trilok Swamini Mata Sita was taken away by Ravana. When Hanuman ji reached Ashok Vatika in search of Mata and asked her to go with him, the mother refused and said that waiting for Sita would be the inspiration for the destruction of Lanka by Shri Ram. If I go with you, perhaps after finding me, Shri Ram will go back, so oh son, let me wait.
O Nandi Maharaj, this is what I am reminding you, wait, someone will definitely come to save this pilgrimage. Have faith like Mother Sita and wait, my share of samadhi will come, waiting for your part is Shiva vehicle.’ Saying this Mahant Panna jumped into the well.
The army of the invaders came, the Avimukteshwar area was demolished. Nandi kept watching this after getting hurt by Jatayu, then one day a queen came, she lifted Mahadev from the lap, Nandi saw that Mother Anusuiya’s affection was being touched on his head, but Nandi was waiting. Centuries passed, Yuga Badla Nandi was counting the days.
One day Nandi saw the revival of Avimukteshwar area, he heard that the king of New India has ordered the rejuvenation of Kashi. One day Nandi’s body was touched by the winds coming from Mother Ganga. It took three hundred fifty-two years to see Mother Ganga. Nandi’s bliss returned, Vishwanath Dham’s supernaturality returned, but Nandi was still looking at Gyanvapi Tirtha, Mahant was looking at Panna.
Nandi’s tenacity overshadowed the reputation of the fragmented works of the new king of India. He understood that the work of Mahadev is incomplete, the promise made to Mother Ganga is incomplete. He ordered that the Gyanvapi shrine be liberated. Mahant Panna, who was buried in the well, smiled, the wait for Nandi is about to end.