The largest river flowing through Harbin is the Songhua River. The Songhua River, the largest tributary of Heilongjiang, is Biboyu. Because it originated from the Chinese-North Korean border from the main peak of the mountain Baitou Mountain Tianchi, the water flow went straight down the Tianchi, like falling from the sky, in ancient times, the Manchu people here called Songgali Ula, meaning "Tianhe", and then the sound translated into Chinese "Songhua River".