The World Health Organization (WHO) works to build a healthier future for all people worldwide. Operating through offices in over 150 countries, WHO staff work with governments and partners to promote the highest level of health. They fight diseases like flu, HIV, cancer and heart disease. WHO also works to ensure safety of air, water, food and necessary medicines. Headquartered in Geneva, Switzerland, WHO supports countries' health coordination and objectives. Some areas of focus include health systems, life-course health promotion, noncommunicable diseases, communicable diseases, and preparedness/response. Major successes include eradicating polio in the Americas by 1994 and smallpox worldwide by 1980.