In the Chinese classic Zhuangzi, there is a legend:
Once upon a time, a gigantic fish named Kun lived in the northern sea. No one knew its true size. This fish could transform into an enormous bird called Peng, measuring thousands of kilometers in length. When Peng spread its wings, they resembled vast clouds across the sky. In one continuous flight, it could soar from the northern sea to the southern sea on the other side of the globe, reaching heights of up to 90,000 li (approximately 45,000 kilometers).
This mythical bird symbolizes an endless, far-reaching journey. Today, people use the idiom "Peng Cheng Wan Li" to wish others a long, successful career or a bright and boundless future.