Madagascar (; Malagasy: Madagasikara, pronounced [ma.da.ɡa.si.kʲa.ra]), officially the Republic of Madagascar (Malagasy: Repoblikan'i Madagasikara, Malagasy pronunciation: [repuˈblikʲanʲ madaɡasʲˈkʲarə̥]; French: République de Madagascar) is a sovereign island country in the Indian Ocean, approximately 400 kilometres (250 miles) off the coast of East Africa across the Mozambique Channel. At 592,800 square kilometres (228,900 sq mi), it is the world's second-largest island country, after Indonesia. Its capital and largest city is Antananarivo. Home to around 30 million people, Madagascar consists of an eponymous main island (the world's fourth largest by area) and numerous smaller peripheral islands. Following the prehistoric breakup of the supercontinent Gondwana, Madagascar split from the Indian subcontinent around 90 million years ago, allowing native plants and animals to evolve in relative isolation; consequently, it is a biodiversity hotspot and one of the world's 17 megadiverse countries, with over 90% of wildlife being endemic. Madagascar was first settled during or before the mid first millennium AD by Austronesian peoples, presumably arriving on outrigger canoes from present-day Indonesia. These were joined around the ninth century AD by Bantu migrants crossing the Mozambique Channel from East Africa. Other groups continued to settle on Madagascar over time, each one making lasting contributions to Malagasy cultural life. Subsequently, the Malagasy ethnic group is often divided into 18 or more subgroups, of which the largest are the Merina of the central highlands. Until the late 18th century, the island of Madagascar was ruled by a fragmented assortment of shifting sociopolitical alliances. Beginning in the early 19th century, most of it was united and ruled as the Kingdom of Madagascar by a series of Merina nobles. The monarchy ended in 1897 following annexation by France, from which Madagascar gained independence in 1960. The country has since undergone four major constitutional periods, termed republics, and has been governed as a constitutional democracy since 1992. Following a political crisis and military coup in 2009, Madagascar underwent a protracted transition towards its fourth and current republic, with constitutional governance being restored in January 2014. Madagascar is a member of the United Nations (UN), the African Union (AU), the Southern African Development Community (SADC), and the Organization Internationale de la Francophonie. Malagasy and French are both official languages of the state. Christianity is the country's predominant religion, but a significant minority still practice traditional faiths. Madagascar is classified as a least developed country by the UN. Ecotourism and agriculture, paired with greater investments in education, health and private enterprise, are key elements of its development strategy. Despite substantial economic growth since the early 2000s, income disparities have widened, and quality of life remains low for the majority of the population. Madagascar is experiencing an ongoing famine, which experts argue is the first to be caused entirely by climate change.