It's probably the section on Winshields Crags, just to the north of the B6318 road near the small town of Haltwhistle in Northumberland. read more
In comparison, the Antonine wall, thought by some to be based on Hadrian's wall (the Gillam hypothesis), was not declared a World Heritage site until 2008. It is a common misconception that Hadrian's Wall marks the boundary between England and Scotland. read more