And there is absolutely no proof whatsoever, that Peter ever went to Rome, was beheaded, and or crucified upside down. Scripture does not speak of any of this.
Scripture never mentions the Great Wall of China either, so it must not exist.
And I guess Clement, Tertullian, Irenaeus, Lactantius, Dionysius of Corinth, Gaius, Eusebius and the rest were all lying about Peter being at Rome as part of a grand conspiracy.
Hearsay, won't stand up in court, sorry. Where is the hard evidence. We have, scripturally, "Greetings from Babylon". That speaks volumes.