What historical event cemented the wristwatch’s role for men, long after the core spring mechanism was perfected?

Answer

World War I

Although Louis Cartier made a wrist-mounted watch for aviator Alberto Santos-Dumont, it was World War I that cemented the wristwatch’s ubiquity for men coordinating infantry and artillery movements.

What historical event cemented the wristwatch’s role for men, long after the core spring mechanism was perfected?
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