In the ancient Northern Ocean, there lived a colossal fish named Kun, whose body stretched for thousands of li.
Later, Kun transformed into a bird named Peng, whose back was like the towering Mount Tai and whose massive wings spread like dark clouds covering the sky.
The great roc bird made its home on the Northern Mountain, waiting only for the whirlwind to rise. When the cyclone came, it would mount the swirling wind, beat its massive wings, and soar into the sky to a height of ninety thousand li. With the blue sky on its back and white clouds beneath its feet, it would fly southward, covering countless thousands of li without knowing how far it must go.
The great roc was flying when it suddenly spotted a sparrow hopping among the grass, wearing a mocking expression, and angrily asked, "What are you laughing at?"
A sparrow, seeing a roc sweeping across the sky, jumped into a bush and said:
"You rely on nothing but the wind to fly so high, yet you act so arrogant!" the sparrow chirped mockingly at the roc. "Look at me—each hop barely reaches a foot, each flight just a few yards, yet I leap and soar whenever I please, free and unrestrained. Without the wind, you can't even lift off. What's there to be so proud of?"
The great roc said nothing more and continued its flight southward, for it knew that with a journey of ten thousand li ahead, it shared no common language with a sparrow whose vision could not see beyond the brush.
Later, the idiom "A Roc's Journey of Ten Thousand Li" came to be used as a metaphor for a bright and boundless future.
Source: *Zhuangzi*, "Free and Easy Wandering"
Meaning of the Idiom: Later, the Chinese idiom "鹏程万里" came to describe a bright and boundless future.