Known in China as Chang Jiang, the Yangtze is the longest river in Asia and the third longest in the world. Originating in a mountain glacier on the eastern part of the Tibetan plateau, the river flows eastward and meets up with the East China Sea at Shanghai. Heavily traveled and highly polluted, the Yangtze is home to at least two endangered species: the Chinese Alligator and the Chinese Paddlefish. What animal was reportedly seen in the river after its species was declared extinct in 2006? Discuss