..... it went from coast to coast across what was to become England.
And in its day, it was pretty effective.
He wisely sited the wall with north facing cliffs or hills to make the wal effectively even higher. At least 25,000 Roman soldiers labored long and hard for five years to build it. They were then garrisoned along the wall in a series of large and small forts.
Our latter day Hadrian wannabes, guys like Duncan Hunter and Tom Tancredo are nowehere near the big thinkers like Hadrian was. They just want to build their stupid border fence in places that will keep the brown-skinners away from their favorite border garden spots.
If they cared about keeping the country 'secure' (against what, I can't imagine ..... surely not against maids and gardeners and wine grape pickers) instead of keeping their neighborhoods whiter, they'd be pushing for a modern day example of a high tech Hadrian's Wall. Instead, all they want is a few score miles of fence here ..... and there .... and there. As if fence avoiders aren't smart enough to make their way to the No Fence Zone.
In my view, their half assed measures tell the truth about what **really** concerns them .....
Bigots. That's all they are. Bigots.