TTBOMK, there are 30 or so known ziggurats, spread out over Iran, Iraq, Kazakhstan and parts of Turkey. Any of those could actually be the fabled tower, or it could be one yet to be rediscovered.
The point is that the ziggurat was not an unusual structure and any city-state with the wealth required might have had one.
true and how would any one know which was the correct one given that the area where ziggurats were built is quite large encompassing a lot more than mesapotamia.