I think that the key can be regarded as a Christian symbol: "I shall give to thee the keys of the kingdom of heaven" and so the Vatican flag should be included.
The flags og Samoa and Papua New Guinea are also questionable; the southern cross is a constellation, and more than a christian symbol, it symbolises the southern hemisphere. The southern cross are also in the flag of Brazil.
But the flag of Vatican City has undoubtedly christian symbol.
The flags og Samoa and Papua New Guinea are also questionable; the southern cross is a constellation, and more than a christian symbol, it symbolises the southern hemisphere. The southern cross are also in the flag of Brazil.
But the flag of Vatican City has undoubtedly christian symbol.