Scholars disagree as to its actual purpose, but most agree that it was built to reinforce the northern border of Britannia – then part of the Roman Empire – and to keep out the ‘barbarians’ from the Scottish Lowlands in the north. It stretched about 73 miles along the neck of current-day Britain & was about 12-20 feet high and 10-18 feet wide (at different locations along it). Hadrian had turrets and small castles constructed along the length of the wall to ensure round-the-clock oversight through his Roman legions, with up to 10 soldiers garrisoned at every checkpoint. Almost 2 millennia old, this wall still stands as a reminder of what was.