Henan province is facing extreme flooding after a year's worth of rain came down in just three days

Horrifying stories have spread of the people in China in floods caused by what authorities say is a once-in-a-millennium event, Guardian reports.

According to the story, Henan province is facing extreme flooding after a year's worth of rain came down in just three days.

Across social media, videos showed hundreds of cars floating down main streets, commuters trapped in metro carriages and crowds of people forming human chains to rescue each other from roads.

At least, according to the report, 25 people have been killed and more than 200,000 displaced by the disaster in the city of Zhengzhou.

See the video below: