Excavations in the Chinese city of Kaifeng have exposed the silted channel of the Bianhe River, an important branch of the Yellow River that once flowed through the city.
In 1147, a scholar named Meng Yuanlao set down his memories of Dongjing, the fallen capital of China’s Northern Song Dynasty, in his book The Eastern Capital: A Dream of Splendor. Meng had lived in Dongjing, which is now known as Kaifeng, before the city was overrun by Jurchen nomads who invaded China from their Manchuria