Hadrian’s Wall is celebrating its 1900th birthday… the perfect time for History Hit to investigate this potent embodiment of Roman dominance.

Dan Snow explores the physical remains of Hadrian’s vast project of 122AD - over 80 Roman miles of wall, turrets and forts, stretching from coast to coast across northern England. Mile after mile of stone marching over the horizon.

But why did the Romans go to all this effort? We dig into the key questions: was the wall a barrier or a porous border; a hubristic vanity project or a vital line of defence; who lived on and around the wall; and why has it endured in popular culture for nearly two thousand years, right up to Game of Thrones?

Dan meets leading experts along the Wall and visits some of the key sites - from Arbeia in the east (where tombstones reveal people here from as far away as Syria) to Birdoswald in the west (where a blatant carving of a phallic symbol shows the Wall was more than just a barrier).

A Roman historian wrote that when the Emperor Hadrian came to Britain in AD 122 he ‘put many things to right and was the first to build a wall 80 miles long from sea to sea to separate the Romans from the Barbarians’.

In this film we discover what that massive engineering and construction project really meant - and the impact it had on Roman Britain and beyond.