After a crazy trading session, the Dow has ended down 1,175 points at 24,345 points. The Dow Jones industrial average has suffered its worst day in over six years. The plunge sent the Dow below 24,000; it hasn't closed below that level since Nov, 29. 

Stocks gyrated wildly throughout the day. If the decline holds, it will be the worst single-day point decline in Dow history. The Dow fell 777 points on Sept. 29, 2008. 

It will also be the first two-day drop totaling 1,000 points for the Dow since August 2015, when investors were worried about the Chinese economy. The Dow was much lower then, so the decline was significantly worse in percentage terms. 

There were also heavy losses on the S&P 500 and Nasdaq indices, which both lost around 3.5%.