Really?! Link? Please? I've always wanted to have something like that. On the wall topic. If you're going to build a 10.000 km wall, you're going to do that industrially. I.e. set up one or more huge factories to churn out pre-fabricated wall segments. Then you need to figure out the logistics (where to put the factories, how to get raw materials there and how to get the wall segments out). A perimeter road will likely need to be built whereever the wall goes, in rough terrain this will be more difficult than building the wall itself. Setting up the wall itself is easy with logistics and manpower sorted out you can probably set up hundreds of km of wall a day assuming the setting up-process is industrialised also and there are many construction crews starting construction at different points. I envisage a construction crew that needs to work like a well-oiled machine (truck arrives carrying wall segment, immediately a crane lifts it off and swings it into the trench that is being made by a power-excavator, the crane rolls forward and the next truck arrives while workers fasten the wall segment securely to the previous one and earth is moved back to fill up the trench). Setting up a 10m wall segment could potentially take a minute, maybe even less. That speed would mean a single crew operating its equipment around the clock could set up maybe up to 15km of wall in a day. Twenty such crews could put down 300km of wall in a day. But as I say, making the roads to carry the trucks and the wall-building crews is going to probably take much longer. What are you going to do with rivers, lakes etc.? Putting nets etc. across has the awkward side-effect that they snag branches, trees and everything else that floats down-river. Also there is the danger of damage due to flooding. It's going to be the "non-standard" bits of terrain that are going to cause the headaches and delays in construction because they need individual solutions. Personally, I think it could be done in five years, in one year with a monstrous crash programme of gigantic proportions.
Interesting premise. The Great Wall of America might be a good name for the book, with a picture of USA map and the wall bisecting the country.
