A country may be an independent sovereign state or part of a larger state, as a non-sovereign or formerly sovereign political division, a physical territory with a government, or a geographic region associated with sets of previously independent or differently associated people with distinct political characteristics. It is not inherently sovereign. Countries can refer both to sovereign states and to other political entities, while other times it can refer only to states. For example, the CIA World Factbook uses the word in its "Country name" field to refer to "a wide variety of dependencies, areas of special sovereignty, uninhabited islands, and other entities in addition to the traditional countries or independent states".
The largest country in the world by geographical area is Russia, while the most populous is China, followed by India, the United States, and Indonesia. The newest United Nations (UN) member is South Sudan. Admission of new members requires the approval of the General Assembly; since 1991, UN membership has been reserved to sovereign states. Microstates are sovereign countries having a very small population or very small land area, usually both; examples of microstates include Vatican City, Monaco and San Marino.