It’s been 25 years since the bull-run that defined the go-go ’80s came to a screeching halt.

The trading slide began in Asian markets, and picked up steam after announcements of U.S. warships shelling an Iranian oil platform in response to a missile attack on an American flagged tanker.

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Programmed trading exacerbated the initial panic by automatically dumping shares and driving markets down faster than anyone thought possible. The Dow fell 22.6% by the closing bell, and markets worldwide continued to drop for the remainder of that month. By Halloween 1987, the U.K. markets were down 26.4%, Hong Kong was down 45.5% and Canada’s stock markets had shed 22.5% of their value.

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Those rapid declines led to the installation of circuit breakers on all the major exchanges, which as recent flash crashes show, still haven’t been perfected a quarter-century later.

Today, the catchphrase question, “Where were you on Black Monday?” continues to be a generational benchmark for people working in, and covering, finance worldwide.

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Which begs the question, “Where were you on Black Monday, 1987?”

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