The District of Columbia, located on the north bank of the Potomac River, is the capital city of United States. The centers of all three branches of the US federal government are located in the city, as are many of the nation’s monuments and museums. Washington, DC hosts 176 foreign embassies as well as the headquarters of the World Bank, the International Monetary Fund (IMF) and the Pan American Health Organization (PAHO). The headquarters of other institutions such as national trade unions, lobbying groups, and professional associations are also located in the District. The greater DC region is also home to numerous government and defense contractors.