Why the stock market crashed?

China's stock market went down 9 percent which made the rest of the world sell their stocks. This flood selling of stocks caused the stock market togo down 416 points in one day. The Dow has lost about $6 Billion in market value which will send their industrial average into the negatives for the rest of the year. During the Great Depression affected more than the United States. During the Great Depression the stock market crashed and a tremendous amount of people lost most if not all of their money. it took years to get out of the debt.