As per the description available in page 387 of Bhai Bala Janamsakhi Guru Nanak Dev Ji came to Manikaran for the welfare and wellbeing of the people of this region, around the year 1574 of the Vikrami Calender. Bhai Bala writes that when they arrived at manikaran Bhai Mardana with the permission of Guru Nanak Dev Ji collected flour and pulses from the local people for langar. Guru Nanak Dev Ji asked Bhai Mardana to lift a stone from the spot where he was sitting. When the stone was removed a pool of boiling hot water fed by a hot water spring emerged. Guru Nanak Dev Ji told Bhai Mardana to tie the pulses in a cloth and to knead and roll the flour in the form of prasadas and throw everything into the hot water pool. When Bhai Mardana did so everything sank and disappeared. Bhai mardana, with a despondent look on his face turned to Guru Nanak Dev Ji for guidance. Guru Nanak Dev Ji asked Bhai Mardana to pray to the almighty l that if the lost food was recovered he would donate one prasada in the name of the almighty. When Bhai Mardana prayed thus, miraculously the food which had disappeared resurfaced, fully cooked. Guru Nanak Dev Ji explained that just as in the case of the lost food, any person who thus prays to the lord, recovers all he has lost. Even today the pool exists and is used to make for the free langar (free community kitchen) at the gurudwara Nanak Dev Ji.
The news of the miracle spread like wildfire throughout the region. People recognized Guru Nanak Dev Ji as a beloved of god. Even the king of this region came and prostrated himself before the feet of Guru Nanak Dev Ji. Guru Nanak Dev Ji in his humble manner counselled the gathered populace that the almighty is omnipresent and omniscient. If you pray to him you will also be blessed. If you spend a portion of your earnings to serve saints and holy people, to build dharamshalas for the welfare of visitors and wayfarers you will attain a place at the almighty’s feet. The visit of Guru Nanak Dev Ji is also predicted by Maharishi Ved Vyas on page 28 verse 33-44 of the Bhavishya Puran.
Today Gurudwara Manikaran Sahib can accommodate more than 4000 people at a time. Here free langar is available round the clock. But this was not always so. This gurdwara is built on what was once a cremation ground. Baba Shri Narain Hari Ji came here with his wife, wishing to commemorate, in the form of a Gurudwara, the visit of Guru Nanak Dev Ji to this place. After looking high and low he was able to locate the exact spot where Guru Nanak Dev Ji uncovered the hot water pool in which uncooked food disappeared, which miraculously reappeared fully cooked. Even today the food is cooked here in big vessels by immersing them in the spring of hot water.