The World Health Organization (WHO) is a specialized agency of the United Nations that is concerned with international public health. The WHO constitution states that its objective "is the attainment by all people of the highest possible level of health." The WHO has played a leading role in many public health achievements, including the eradication of smallpox, the containment of the HIV/AIDS pandemic, and the formulation of global health strategies such as the WHO Framework Convention on Tobacco Control. The WHO is headquartered in Geneva, Switzerland, and has six regional offices and more than 150 country offices around the world. The WHO also has a partnership with the United Nations Children's Fund (UNICEF) to provide immunizations and other health interventions to children in developing countries.