1991: The New York Stock Exchange begins after-hours trading for the first time, as two "crossing sessions" of trades among institutional investors extend the trading day to 5:15 p.m.

Fact Book for the Year 1997 (New York Stock Exchange, 1998), p. 91

1990: Jubilant Germans, inspired by Ronald Reagan's speeches, Mikhail Gorbachev's perestroika, and the resignation of East German strongman Erich Honecker, begin tearing down the Berlin Wall — toppling the most notorious symbol of Communism for all the world to see. Unsettled by the change, the Dow Jones Industrial Average closes down 4 points at 2929.70.

1986: Real-time market data takes a big leap forward (for better and for worse) as Standard & Poor's begins disseminating the value of the S&P 500-stock index every 15 seconds. Previously, the index price was updated once a minute. It's not entirely clear why the ability to check the market 1,559 times per day should be important to investors, but some people still consider this progress.

S&P 500 2001 Directory (Standard & Poor's, New York, 2001), p. 9.