It's said,there was a luxuriant laurel tree standing in front of Guanghan Palace on the moon.It was more than 1500 feet high.A man often cut it at the bottom of its trunk.But each time the cuts healed up automatically right away after he chopping.For thousands of years,this kind of chopping and healling-up continues and the laurel tree keeps standing there.It is said the chopping man was called WuGang,from Xihe of Han Dynasty.He once followed the immortals and paved the way to heaven.Then he made a mistake and was exiled to the moon by the immortals to continued this kind of futile efforts every day as a panishment to him.