Mysterious Ancient Circles in Jordan

This perfect circle in the Jordanian desert is four hundred meters

wide,

and no one knows who made it.

From the ground, it's just a low wall of stones you could

step

over. But seen from above, its shape is

almost flawless.

There are at least twelve of them across Jordan and

Syria,

and nearly every one is the exact same size.

Whoever built them had no writing, no metal tools,

and no way to fly, yet each ring is a near perfect

circle.

And here's the strangest part: the circles have no entrance, no

gate, no door. To get inside, you had to

climb over the wall. They are at least two thousand years

old, and many believe they were built long before humans learned

to write.

Archaeologists have studied them for a century and still can't agree who

made them, how they got them so perfect, or why.

Twelve perfect circles sealed shut, drawn by

people who could never see them from the sky.

What were they for?