Guyana (pronounced /ɡaɪˈɑːnə/ or /ɡaɪˈænə/), officially the Co-operative Republic of Guyana, is a sovereign state on the northern mainland of South America. It is, however, included in the Caribbean Region due to its strong cultural, historical, and political ties with the Caribbean Community (CARICOM). Guyana is bordered by the Atlantic Ocean to the north, Brazil to the south and southwest, Suriname to the east and Venezuela to the west. With 215,000 square kilometres (83,000 sq mi), Guyana is the fourth-smallest country on mainland South America after Uruguay, Suriname, and French Guiana. The region known as "the Guianas" consists of the large shield landmass north of the Amazon River and east of the Orinoco River known as the "land of many waters". Originally inhabited by several indigenous groups, Guyana was settled by the Dutch before coming under British control in the late 18th century. It was governed as the plantation economy of British Guiana until independence in 1966, and officially became a republic within the Commonwealth of Nations in 1970. The legacy of British rule is reflected in the country's diverse population, which includes Indian, African, Amerindian, and multiracial groups. Guyana also has the distinction of being the only South American nation in which English is the official language. The majority of the population, however, speak Guyanese Creole, an English-based creole language with slight Dutch, Arawakan and Caribbean influences. In addition to being part of the Anglophone Caribbean, Guyana is one of the few Caribbean countries that is not an island in the West Indies. CARICOM, of which Guyana is a member, is headquartered in Guyana's capital and largest city, Georgetown. In 2008, the country joined the Union of South American Nations as a founding member. Approximately three quarters of the west of the country are claimed by Venezuela, specifically 159,542 square kilometres, accounting for 74.21% of the territory, zone called by this as Guyana Essequiba. Its other neighbour, Surinam, claims for itself a part of the eastern territory southeast of the country specifically about 15,600 square kilometres called Tigri Area which currently accounts for 7.26% of the country.