The 1973 event that helped trigger a worldwide stock-market crash was the 1973 oil crisis.
The crisis began in October 1973 when members of the Organization of Arab Petroleum Exporting Countries announced an oil embargo against countries supporting Israel during the Yom Kippur War. Oil prices rose sharply, creating inflationary pressure and increasing costs for transport, manufacturing, and households.
The shock contributed to stagflation and a major bear market in many countries. In the United States, the Dow Jones Industrial Average fell deeply between its January 1973 peak and December 1974 low. The oil crisis was not the sole cause of the market decline: inflation, recession, and monetary conditions also played important roles.