This nail fascinates me. It is hammered in to a tree stump and it serves no purpose (and never has as far as I can remember). Today there where two, small metal rings around it like someone had used it for a game of quoits.
One of the myriad mysteries of daily life. A fascinating photograph. I'm just as curious as you are to find out what the story is here. Those rings look like they could be old keyrings, maybe.
and a mystery :-)