Consisting of concentric circles of stone surrounded by a moat (called a "henge"), Stonehenge was constructed in several stages over thousands of years.
Remember, I was talking about how targets in archery are usually circles, what we would call " concentric circles" – circles that go around other circles.
Then I went to the—an office supply store, got a map of the U.S., and got a compass and a wax crayon, and I drew concentric circles out 200, 300, 400 miles.