Nanda Parbat was a hidden city in the Himalayas. It was a place where time moved differently and was often sought out, despite the great difficulty in finding it. Bruce Wayne found it and used it's teachings to create a backup plan against Simon Hurt.
Created in Tibet as Nishapur, the city was a dark haven that was ruled by black magic despots. Ra's al Ghul was known to have connections there, as the purest Lazarus Pit was located in the city. The despots had designs to open up portals to afterlives, specifically Hell. However, benign wizards began to fight against the despots and banded together to build a new city of enlightenment over Nishapur. This new haven, as it came to be known as Nanda Parbat, forever began to reflect the delicate balance of good and evil.