NOTE: Jerusalem is called the “great city” (Rev. 11:8). Babylon is also called the same (Rev. 18:10-21). Even so, I don't think that the Harlot is a city.
I don’t think that the Harlot is a natural city. I think that it is a spiritual network or organization that is both a religion, a philosophy, and a well-organized secret “government.” In some ways, it is no different from many special-interest groups. But it is world-wide and has a very strong organization.
People who start down this path, rarely turn back. Why is this?
The combination of these two forces is enough to keep most of the members loyal to the organization (or at least quiet about the faults and workings of the organization).
How does the Harlot reign over kings and people? There are basically two way to get power over people:
In order to hold to your principals are you willing to lose your job? your house? your position? your reputation? all that you hold dear? Or does the Great Harlot hold you captive by these things?