Sharks in the North Sea - Faroe Islands

All over the Faroe Islands I was noticing these stone circles.

 

I asked the locals what they were and could never really get a clear answer as to what they were for.

 

Can anyone enlighten me?

 

For disclosure, I blended two shots here. The clouds and light rays are from a shot I took in Scotland last year.

 

Thanks for looking

Gavin Hardcastle - Fototripper

 

 

Done