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The Boston tea party, of december 16th, 1773.

This was a decisive military action against the English, which basically was the start of the United States as we know it.

As the US is now leading the Western world, I believe we can clearly state that this battle has had a great impact on the world as we know it, and on a lot of the events that have taken place since on world scale. 

For instance:

How would WWII have finished, if the Boston tea party had never taken place? 

Even the battle of Waterloo (I am currently about 15km away from Waterloo (Brussels, Belgium) while writing this btw ;-) ) would've been different, or not have taken place, if the Boston tea party would not have happened (the army of the British Duke of Wellington was at about half force when going to battle against Napoleon, because a large part of his army was still in the US, or had died there).

I would say World War 2 and the reason why is that the world was threatened by one countries dominance. Germany wanted to rule the world and they came mighty close to achieving it. Europe fell too quickly and weren't prepared. If it wasn't for the Russians , English and the Americans the world would be a total different place today.

There are many important battles through the ages but this one stands out for me as it was crucial for the world powers to come together. This will make any country think now that they arent fighting one country but others will get involved. keeping world peace is crucial to the stability of the world.

But within WW2, any battle or engagement that you felt is the turning point?

Since @bozz took my WW@ answer I'll go a different route

Waterloo

Think about what the world was like then and what would have happened if Napoleon had won at Waterloo.

Would Germany even exist? What would have happened after Napoleon died a few years later of stomach cancer and his 13 year old nephew Napoleon III would have assumed the throne.? Most likely a civil war would have ensued.

What would the world be like now with 200 years of chain reaction/alternate timeline from that single event and what followed?

Baguette and cheese anyone?


If Napoleon had triumphed at Waterloo, much of the world might be speaking French today

Ahh oui oui :)