One day, a frog that lives at the bottom of a shallow well speaks in high spirits to a turtle of the Eastern Sea.
“My life in the well is really a joy! When I jump out of the well, I climb onto the outside rail. When I return, I rest in a crack inside the well. As I swim, the well water covers my armpits but my head rests above it. Playing in the mud, I bury my feet in it. Look at the cockles, crabs, and toads around me—who lives as happily as I do? Furthermore, this well is my own territory, serving my own enjoyment. What a wonderful life this is. Why don't you come in to see for yourself?”
At the frog's invitation, the turtle prepares to enter the well. But before he can move his left leg, his right leg has already been blocked by the well's rail. He retreats to the well side, and starts to speak to the frog about the sea.
“How big is the sea? Even a thousand miles would not describe its breadth; ten thousand feet would not describe its depth. During the time of the Great Yu (of Xia Dynasty), there were nine years of heavy rainfall out of ten, and flood ravaged all over the land, but the sea level did not seem to rise. During the time of Tang (of Shang Dynasty), there were seven years of drought out of eight, and the land surface cracked, but the seashore did not seem to recede.  Not to be affected by the passage of time or wax and wane of tide—thus is the great joy of living in the Eastern Sea.”
Hearing about the sea, the frog is shocked. It starts to sense the smallness of its own life in the well.
Note:  Xia and Shang are both early dynasties before 11th century BC.
Source: “Zhuang Zi – Autumn Waters” By Zhuang Zi (circa 369-286 BC).