The Architect told Neo that there were other Neos before him and that they each started with a new Zion so does this mean there are probably relics of past Zions located on the earth that are randomly built by the machines and then the location 'forgotten' so the Architect can test the system?
That's true. It could be something in the Matrix where they go to a different country and what they're really doing is entering the Martix of another group of people but they haven't moved physically.