Not only in China, but such land had suddenly appeared in many countries out of nowhere 21 years ago.
The land ownership was owned by a mysterious person, who for some reason could buy land all over the world.
When the apocalypse arrived many of the military officials thought the land was some kind of gift to humankind to protect themselves and tried to invade it, but to their dismay, even a nuclear bomb couldn't blow away the electric walls.
It was true for every other nation.
This made the leaders of the nation wonder whether the zombie virus originated from the vast empty land protected by an electric wall.
There was also a conspiracy theory that the people who were the real culprit behind the zombie virus were hidden within these mysterious electric walls, biding their time and watching the world tear itself apart.
Some believed that those inside the walls held the key to either saving or destroying humanity.