Dow down 416 pts! - Why?

The Dow Jones Industrial Average went down 416 points on Tuesday because in China the market went down 9%. It interuppted the equilibrium that everyone was in and effected my stocks as well. This disaster brought 416 pts on the Jones Dow making many companies loose millions of dollars. A lot of people sold most of their stocks causing it to decline. The China and U.S are close trading partners and the decrease in China affected the U.S as well. It wasn't as bad as the other famous declines such as the stock market crash during the Great Depression, when all of America fell into depth. During this time, my stocks are doing pretty well because I didn't buy much to begin with, but after everything becomes normal again I might buy more stocks.