I've built one or two in my time, just added it up and there's just short of 69,000m² of walls designed and or built by me in the UK with another 150,000m² in the middle east and another 410,000m² built in Asia. Biggest height in one lift is 27m, biggest in tiered walls is 56m while the heaviest loaded one has a six lane highway bridge sat on it.
In fact if you took that area you could build a wall 2 bricks high around the entire coastline of Ireland, I wouldn't have a bloody clue about where to start with the planning permission over there though Baz.