The giant_city_builder_sandbox_map.zip file you have requested: Custom Maps / Giant City Builder Sandbox Map - 4.01mb is not available. Perhaps try browsing all files for the game Black & White 2 and upload any files you want to share or are missing. This is the only information we could locate:
You start with only a town centre, a creature, and 10 villagers. Build up your city, and farm and breed like crazy to stop your people dying out. I'd like to see if someone could really fill this land with buildings.