Undated file photo provided by Qinglong Wu of Nanjing Normal University shows the Jishi Gorge in northwest China's Qinghai Province. Scientists have found what could be geological evidence of a legendary flood tied to the establishment of the first dynasty in China, Xia, and even the beginning of Chinese civilization, a study published in the U.S. journal Science said Thursday. In the new study, Qinglong Wu and colleagues reported geological evidence for a catastrophic flood on the Yellow River about 4,000 years ago, including remains of a landslide dam and dammed lake sediments. (Photo/Xinhua)