This photo shows crowds gathering outside the New York Stock Exchange during the 'Black Thursday', 1929, October 29th, the day Wall street suffered its worst day ever. - 

This final note today. A couple of 'em actually.

First of all, just a nod to history. Today's the 19th of October. On this day in 1987, Wall Street treated us to something that's become known as Black Monday: the Dow Industrials were off almost 22 percent.

Put that in today's context? That's a drop of 2,600-something points. There are circuit breakers that'd stop that nowadays, but still. Something to think about.

Follow Kai Ryssdal at @kairyssdal