The Seven Hills of Rome
One of the canards one often here's from people who deeply despise Catholicism is a reference to the Church as the great whore of Babylon who sits astride the city of seven hills, i.e. Rome.
The problem is, the Vatican isn't one of the seven hills! As any reference source will tell you, the seven hills of Rome are: the Palatine, the Capitoline, the Quirinale, the Viminale, the Esquiline, the Caelian, and the Aventine. While some of the people who make the claim about Catholicism and the seven hills seem to be aware of this and work around it, most of them erroneously define the Vaticanus as one of the seven, apparently unaware that the Vaticanus is on the other side of the Tiber from "downtown" Rome (it used to be outside the city of Rome), and has never been numbered among the seven hills.
But if history won't stand in their way, why should geography?