Was Peter crucified upside down?

Is this true? And if so, where is it? Because I don't think it is in the Bible, if it is please tell me where. Don't just say yes he was, I want to know why you are so sure he was. And I already know if he really was, why he was, so don't bother with that part. :D
Update: I'm only asking because I was looking at a picture of an upside down cross and it said that that was how Peter was executed but I was just wondering if there was actually any real proof.
Update 2: LOL woops.
when I said And I already know if he really was, why he was, so don't bother with that part
I mean that if he really was then I know why he was. not that I knew if he was or not, gosh im a tard
22 answers 22