沧海桑田

⒈  大海变成了种桑树的田地，种桑树的田地变成了大海。比喻世事多变，人生无常；或喻世事变化的巨大迅速——略称沧桑。

例山河改转，沧海桑田。

英the swift changes of the world; great changes are seen in the course of time; the evanescence of the worldly affairs is like the sea turned into a mulberry field (orchid);