Switzerland

The Swiss Confederation, more commonly known as Switzerland, is one of the five countries in the world. It is the only country whose boundaries weren't altered by the Third World War, and the majority of its territory is surrounded by the Roman Empire.

The mystery
Not much is known about the status of the country today: the Confederation shut down its borders at the start of the war, and nobody has been allowed to enter or leave the country ever since.

Some think that Swiss spies are all around the world, gathering intel for the Swiss government, but it has never been proven to be true.

In the years, many diplomatic attempts at dialoguing with the Swiss government have been tried by the four major powers, especially by the Roman Empire, but each and every time there was no response by the Swiss. Nobody from anywhere in the world has ever reportedly been able to enter Switzerland: every proof of someone doing it has been deemed fake.

It is thought that, although there are no reports of this actually happening, even if someone managed to enter Switzerland, they would be instantly killed by either the border police or a citizen: it is well known that everyone in the country is part of the military, and every man and woman over the age of 18 has been trained to use firearms.