Grimsey Island, Iceland
So those clever Icelanders made this marker to indicate the position of the current arctic circle. Every so often the reposition it. No easy task since it is about 10 or 12 feet in diameter! There's a hole cut through it to show alignment with the North Pole.
And, an enquiring mind might ask how someone goes about moving this concrete behemoth. Well, I did.
Turns out it is hollow and filled with styrofoam peanuts. Or, so told me by the proprietor of "The Store".