Now that the markets are a spectator sport, you need a good, all-visual way to watch the carnage.
The best free dashboard is this Finviz Futures page, which shows graphs of 48 markets on one screen, so that you can follow in one glance. Pro tip: On the upper right, adjust the time period for hours or days or months. (Don't get too excited about the surging "VIX" market-that stands for Volatility Index. Its upswing means that all hell is breaking loose.)
For U.S. markets, click over to the Finviz U.S. page, where you can see that, as of this writing, 92% of New York Stock Exchange stocks are declining and the market is a literal blood bath, with every single major U.S. stock colored blood red.