18. Big Circles
Around Jordan, in the Middle East, you’ll find what’s known as the ‘Big Circles’- large circular enclosures 220 to 450 meters in diameter.
The largest of them is nearly three times bigger than the Olympic running track and were built almost 2,000 years ago.
They’re made using roughly-cut boulders, nearly a meter high, which, with a little effort, should be easy enough to arrange.
But what’s baffling is why they were constructed in the first place, and how they managed to create such a large, nearly-perfect circle in the middle of nowhere.