*Edit: lol my bad for spelling FITNESS wrong in the title facepalm
I found this video which is really interesting.
Also The Heat Map I'm linking will take you an area in the middle of the Utah desert and the first thing you can see is what seems to be a perfect circle but isn't tracked with any path leading to it. Pretty Odd.
*This video explains in more detail (skip to 9:48 if it doesn't already take you there in the embed)
I'd say if this interests you keep an eye out for future discoveries, I most certainly will (^:
Thanks!