The World Health Organization (WHO) was established in 1948 as a specialized agency of the United Nations. It is responsible for global health leadership and works with its 193 member countries and 6 regional offices to improve health, keep the world safe, and serve the vulnerable. The WHO aims to attain the highest level of health for all people through its vision, mission, and priorities which guide its work in public health areas like disease control, health services, and environmental health. It plays a key role in setting standards, policy, technical support, and monitoring global health trends. Some of the WHO's major achievements include eradicating smallpox and establishing primary health care through conferences like Alma Ata.