Which stock exchange crash helped begin the Long Depression of the late 19th century?

The Vienna Stock Exchange crash helped begin the Long Depression of the late 19th century.

A speculative boom in Austria-Hungary ended with the Vienna Stock Exchange crash of May 9, 1873. The event followed years of rapid railway construction, property speculation, and easy credit. When confidence broke, prices collapsed and several financial institutions failed.

The panic spread through interconnected European markets and soon reached the United States. In America, the failure of the banking firm Jay Cooke & Company in September 1873 helped trigger a severe financial crisis and the closure of the New York Stock Exchange for roughly ten days.

Historians debate the exact boundaries and causes of the Long Depression, which lasted for years and affected countries differently. It is not the same event as the Great Depression of the 1930s. The Vienna crash is important because it shows how international capital flows could transmit a market panic across borders even before modern electronic trading.