Comments by "DrScopeify" (@drscopeify) on "Did WW2 start in 1937 or 1939?" video.

I think that an important aspect is the safety of ocean passage. On September, 3rd, 1939, just hours after the British declared war, the first Uboat attack had taken place, sinking the private owned commercial ship the SS Athenia - in my view that is the first shot of WW2 as a true global conflict becasue now you have the safe passage ocean ships and trade in danger around the globe. The result is world wide preparations and re-activation of costal defenses.
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I think that an important aspect is the safety of ocean passage. On September, 3rd, 1939, just hours after the British declared war, the first Uboat attack had taken place, sinking the private owned commercial ship the SS Athenia - in my view that is the first shot of WW2 as a true global conflict becasue now you have the safe passage ocean ships and trade in danger around the globe. The result is world wide preparations and re-activation of costal defenses.
4