What was the first major international stock-market crash of the modern era, beginning in October 1929?

The Wall Street Crash of 1929 was the first major international stock-market crash of the modern era, beginning in October 1929.

It followed a period of rapid share-price growth, widespread speculation, margin borrowing, and optimistic expectations in the United States. Major panic selling occurred on Black Thursday, Black Monday, and Black Tuesday, although the market’s decline continued for years rather than ending after those sessions.

The crash spread through international financial links and contributed to the Great Depression. It damaged investor wealth and business confidence, while falling demand, bank failures, debt problems, and protectionist policies deepened the economic collapse. The Dow Jones Industrial Average did not return to its pre-crash peak until 1954.

Earlier crises, including the Panic of 1873, were important financial shocks, but the 1929 crash is usually identified as the first modern crash with a truly international economic impact. The answer names the event, not a single day within it.