North.
Yidu Town.
Northern Territory Federation.
A river flows through the towering walls, known as the Barrier River.
Beneath the southern wall, the outermost layer is an iron fence about six or seven meters high, each bar as thick as a washbasin, with gaps of about twenty centimeters between them.
A meter outside this fence, there is another layer of fences, even tighter, about as thick as a thigh, but with smaller gaps, only less than ten centimeters.
Two meters further, there is another layer with gaps as small as a cup mouth, only five centimeters wide.
Three layers of fences, with larger gaps and diameter the closer they are to the outside.
Above these fences is a tall wall.
The fences are embedded underwater, stabilized firmly by the gravity of the wall above.
On the northern part of the wall, the same approach is applied.
Walls, like a Great Wall, connect two mountains, with the Barrier River flowing between them.
A torrential rain pours down.
