International organizations with a W at the beginning or an O at the end have headquarters in Geneva, Switzerland. Eg: WIPO, WHO, WMO, WTO, ILO, ISO. (The exception is IMO whose headquarters is in London.) 2. The organisations related to funding or money, their headquarters are located in Washington DC, US. Such as IMF, World Bank. 3. Atomic / Petroleum / Industrial Development Organization is headquartered in Vienna, Austria. Eg: UNIDO, IAEA, OPEC. 4. Economical and Educational organisations have their Headquarters in Paris, France. Such as - OECD, UNESCO. 5. If the name of an organization is associated with UN or E / F, its headquarters is in New York. Such as: - UNIFEM, UNICEF, UNFPA, UN. 6. The names of the organizations that indicate food is headquartered in Rome, Italy. Such as: - IFAD, WEP, FAO. 7. With A / B / C / D / F at the beginning and end, it is headquartered in Washington DC, USA. Such as: - IMF, IFC, IDA, IDB, IBRD, ICSID.