turn around vs turn behind

[Daemon99]

1) I turned around to see who it was.
2) I turned behind to see who it was.

Can someone please tell me if both the above sentences are correct and mean the same thing?
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Non-native speaker of English
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I intend to live forever - so far, so good.

[Mister Micawber]

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Only #1 is correct. I turned around. I looked around/behind..
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Native English teacher at Mister Micawber's