On this day in 1972, the Dow Jones industrial average closed above the 1,000 mark for the first time in its history. International Business Machines led the way, moving up more than 11 points, to 388. One trader remarked: “This thing has an obvious psychological effect. As for the permanence of it — well, I just don’t know.” The New York Times, meanwhile, compared the milestone to “the initial breaking of the four-minute mile,” noting that the stock exchange resembled a carnival:

At 3:29 P.M., red light bars flashed on above and below each of the time clocks surrounding the trading floor of the New York Stock Exchange. This was the traditional visual signal to show that one minute of training time remained. At the same moment, a bell began clanging on the speaker’s rostrum — the auditory warning.

Traders, brokers and clerks on the floor — aware that history was in the making — broke into cheers that lasted about 20 seconds. Some paper was tossed in the air and drifted down like confetti.

Said another broker, “There’s a sort of renewed confidence in the whole economic outlook.” Ah, those were the days. The market finished today off more than 337 points, down almost 4%. And shares of IBM now sell for just over 80.

Update: See the comments for an explanation of the impact of splits on IBM’s stock price. And then if you can figure it out, explain it to me. Thanks.