Wu Gang Felling the Osmanthus Tree

Legend has it that the woodcutter Wu Gang committed a mistake while cultivating immortality in the mortal realm. Enraged, the Jade Emperor banished him to the Moon Palace. The Emperor pointed to a cassia tree on the moon, five hundred zhang tall, and said, "If you can chop down this tree, you will achieve immortality and return to the mortal world." However, this cassia tree possessed a magical self-healing ability; every time Wu Gang swung his axe, the wound would immediately close. Thus, Wu Gang was doomed to endlessly chop the tree in the Moon Palace.