Wall Street fell for a fifth consecutive trading session amid a dramatic global sell-off as fears over China's slowing economy intensified.
In a volatile day of trading, the Dow Jones briefly plunged more than 1,000 points, then almost recovered before closing 3.6% lower at 15,871.35.
The S&P 500 closed 3.9% lower at 1,893.21, putting it officially in "correction" territory - a drop of more than 10% since its peak.
The Nasdaq lost 3.8% to 4,038.6.
There were no winners at all on the Dow. US bank JP Morgan was the biggest loser, dropping 5.3%.
The sharp falls were driven by ongoing fears over the health of the Chinese economy.
China's central bank devalued the country's currency, the yuan, two weeks ago, raising fresh concerns that a slowdown in the country's economy was worse than originally feared.