Stocks on Wall Street tanked today.

Here are the lowlights, as compiled by Reuters:

• S&P 500 turns negative for year.
• S&P closes below 200-day moving average.
• Global growth fears weigh on stocks.
• Dow off 2.2 percent, S&P off 2.6 percent, Nasdaq 2.8 percent.

"It is going to be a long week," said Jim Maguire Jr., a NYSE floor trader at E.H. Smith Jacobs told Reuters. "The bid is not here in the market."

"Investors have made the shift from Washington to what I'm calling economic realities," added Fred Dickson, chief market strategist at The Davidson Cos. in Lake Oswego, Oregon.

Here's the real reason why everyone on Wall Street is suddenly spooked.

It's the weakening U.S. economy, of course. And big parts of the rest of the world, too.