As Saudi Arabia developed from the days after WWII to the major supplier of oil, both US and UK influences came into play in electrification of the desert Kingdom, as well as other parts of the Mid-East. Under UK (and other European) influence, the power systems being developed in the region operated at 50 Hz. Under US influence, regional generation, transmission and distribution was developed as a 60 Hz system. Saudi Arabia is the only country in the mid-East with a large 60 Hz system.