Wide Wednesday: Ring/Circle

Bobsblips would like a photo of a ring or circle for today's Widwed challenge.

Can you work out what this is? It's not Photoshopped on (even if it looks like that) and it doesn't belong to any of ET's friends.

My Editor thinks the photo looks a bit like an eye - but that's because the photo was taken with a fisheye lens -a nd she has a good imagination!