Arjuna Sees Hiranyapura and Learns Its Origin
Returning from battle, Arjuna spots a celestial city drifting through the sky — jewel-laden, impossible to conquer, avoided even by the gods. He asks Matali what it is, and learns the story of the boon that made it invulnerable — and the single condition that will undo it.
Arjuna was returning from his mission when he saw it: another city, suspended in the sky, drifting like a cloud that had decided where it wanted to be. It blazed with the radiance of fire and sun. Its trees were covered with jewels. Colourful birds with sweet voices moved through its branches. It had turrets, entrances, four gates — and it was filled with asuras who were always happy, armed with spears, swords, clubs, bows and maces.
He turned to Matali. "What is this that I see here?"
Matali told him the story.
There were once two daitya (asura) women named Puloma and Kalaka. They had performed austerities for a thousand celestial years — a span of time that would break most beings. When they finished, the self-created god Brahma himself appeared to grant them a boon.
They chose carefully. They asked that their sons should not suffer much. And they asked that their sons should be incapable of being killed by the gods, the rakshasas or the serpents.
Brahma granted it. And he gave them something more: this city, Hiranyapura — the city of gold — that roams through the sky at will. It was full of every object of desire, devoid of sorrow and disease. The immortals themselves avoided it. No god, yaksha, gandharva, serpent, asura or rakshasa could conquer it.
But Brahma had set one condition into the boon. He had destined that the Kalakeyas and Poulamas — the sons of those two women — would die at the hands of a human.
Arjuna looked at the drifting city. He understood what Matali was telling him. Aranyaka Parva, Chapter 467