In ancient legend, the northwest corner of the sky collapsed and the southeast corner of the earth sank, leaving the land flooded with raging waters and engulfed in spreading flames, while ferocious beasts and giant birds preyed on humans, pushing humanity to the brink of extinction.
The goddess Nuwa, with a human head and serpent body capable of seventy transformations in a single day, resolved to save humanity—the very people she had helped create with the aid of other gods. She smelted five-colored stones to patch the collapsed sky, severed the legs of a monstrous turtle to prop up heaven's four corners, slew the black dragon that stirred up storms, and used countless reeds' ashes to stem the great flood. Thus the waters receded, the fires died out, the sky cleared, and the people were saved.
Another myth tells of a kingdom beyond the Eastern Sea, between the Sweet Waters, ruled by the sovereign Di Jun. His wife, Xihe, was the sun goddess. She gave birth to ten suns and bathed her solar sons in a great lake called Gan Yuan, often churning the waves into a riot of rainbows, a breathtaking sight.
Both myths tell stories of humans conquering and controlling nature. The idiom "Mending the Sky and Bathing the Sun" is used to describe one's ambition and power to overcome and harness nature. Later, this idiom also came to symbolize immense achievements.
Source: *Huainanzi*, Chapter "Survey of Obscurities"; *Classic of Mountains and Seas*, Chapter "Great Wilderness of the South"
Meaning of the Idiom: Later, the Chinese idiom "补天浴日" came to describe one's ambition and power to overcome and harness nature.