11. How much earth was dug from the Hadrian’s Wall ditch?

Since the ditch does not run for the whole length of the curtain wall, with gaps in Wall Miles 34 to 45, 67 to 70, and possibly 73 to 75, it may only have been around 95km long. It has been calculated that this would require the removal of around 1.1 million cubic metres or around 371,000 man-days ditch construction.

Further reading: Hill 2006