Saint Vincent and the Grenadines, part of the Lesser Antilles, is an island country in the Caribbean Sea. Proximate countries include Grenada, Saint Lucia, and Barbados. The geography of the country is volcanic and mountainous. The government system is a parliamentary democracy and a Commonwealth realm; the chief of state is the queen of United Kingdom, and the head of government is the prime minister. Saint Vincent and the Grenadines has a mixed economic system in which there is a variety of private freedom, combined with centralized economic planning and government regulation. Saint Vincent and the Grenadines is a member of the Caribbean Community (CARICOM) and the Organization of Eastern Caribbean States (OECS).