What was the Date of internet invention?

I don't exactly know the date but the internet was invented by the US Department of Defence as a means of communication if we were attacked by Russia in 1969. The WWWwas invented by an Englishman called Tim Berners-Lee in Switzerland in 1989. Some people say development started in 1957 when the Soviet Union launched Sputnik 1, the 1st satellite.

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