Some 2,300 years ago a Greek adventurer named Pytheas set out on an astonishing expedition: to find out what lay in the fabled lands of Northern Europe. Rumours abounded of these fearsome barbarian territories, but Pytheas was the first literate man ever to visit them.
Here Barry Cunliffe re-creates his staggering journey as he sailed to the islands of Britannia, home of our distant ancestors - the "tattooed folk" - and beyond, all the way to Ultima Thule, the mysterious Arctic limits of the known world . . .