It is the last thing the residents of Chongqing would have expected to see.
But the Yangtze river, which runs through the city in south-western China, turned a bright shade of orange-red yesterday.
The waterway where the Yangtze met the Jialin River provided a fascinating contrast as the red started to filter into the other river.
While officials investigate the cause of the colouring, one fisherman went about his daily business as if nothing had happened.
Others were so amazed that they collected samples in water bottles.
Although the cause is yet to be determined, this is not the first time a river has turned red in China.
Last December, the Jian River in the city of Luoyang, in the north Henan province, turned red after becoming polluted by a powerful dye.
The dye was being dumped into the city’s storm drain network by two illegal dye workshops.
Officials raided the factories to shut them down, and then disassembled their machinery.
According to chapter 16, verse 4 of the Bible’s book of Revelations, one of the signs that Armageddon is near will be an angel pouring a bowl into the rivers, turning them into blood.