Perhaps the most remarkable feature of the crisis of 1914 was the closure of the world’s major stock markets for up to five months. The Vienna market was the first to close, on July 27. By July 30 all the continental European exchanges had shut their doors. The next day, London and New York felt compelled to follow suit. Although a belated settlement day went smoothly on November 18, the London Stock Exchange did not reopen until January 4. Nothing like this had happened since its foundation in 1773. The New York market reopened for limited trading (bonds for cash only) on November 28, but unrestricted trading did not resume until April 1, 1915. Nor were stock markets the only ones to close in the crisis. Most U.S. commodity markets had to suspend trading, as did most European foreign-exchange markets. The London Royal Exchange, for example, remained closed until September 17. It seems likely that, had the markets not closed, the collapse in prices would have been as extreme as it would be in 1929, if not worse.
(h/t the Belmont Club)