Watch the Dow's crazy day unfold in this live shot from the New York Stock Exchange

U.S. markets are gyrating wildly on Tuesday, after a steep global sell-off. The Dow opened with a loss of more than 500 points before turning positive and quickly climbed as high as a positive 367 points. It has been bobbing between positive and negative territory all morning.

On Monday, the S&P 500 erased its gains for the year and closed 4.1 percent lower, its worst day in six years. There was no specific driver for the sharp decline.

Stocks extended last week's plunge that was fueled by worries about rising interest rates.