Wall Street is already calling it "Black Monday."
The DOW opened down 1,000 points, and the blue chip index has been down 400 points or more for most of the morning.
A crash on the Shanghai Stock Exchange is what started this. With Chinese economic growth slowing, Chinese stocks have lost 40% of its value since June.
Keep in mind that the Thursday and Friday trading sessions had already brought the DOW down almost 900 points.