Recently discovered stone tools and circular structures on the Isle of Skye suggest humans from the Old Stone Age traveled all the way to the frigid northwest edge of Scotland.

This boundary-pushing endeavor took early humans in northern Europe to the "far end of everything", according to a new paper from an international team of archaeologists.

"This is a hugely significant discovery which offers a new perspective on the earliest human occupation yet known, of north-west Scotland," says lead author and archaeologist Karen Hardy from the University of Glasgow.