Nigeria has been home to a number of kingdoms and tribal states over the millennia. The modern state originated from British colonial rule beginning in the 19th century, and took its present territorial shape with the merging of the Southern Nigeria Protectorate and Northern Nigeria Protectorate in 1914. The British set up administrative and legal structures whilst practising indirect rule through traditional chiefdoms. Nigeria became a formally independent federation in 1960. It experienced a civil war from 1967 to 1970. It thereafter alternated between democratically elected civilian governments and military dictatorships until it achieved a stable democracy in 1999, with the 2011 presidential election considered the first to be reasonably free and fair.
Nigeria is often referred to as the "Giant of Africa", owing to its large population and economy. With 186 million inhabitants, Nigeria is the most populous country in Africa and the seventh most populous country in the world. Nigeria has the third-largest youth population in the world, after India and China, with more than 90 million of its population under age 18. The country is viewed as a multinational state as it is inhabited by over 500 ethnic groups, of which the three largest are the Hausa, Igbo and Yoruba; these ethnic groups speak over 500 different languages and are identified with a wide variety of cultures. The official language is English. Nigeria is divided roughly in half between Christians, who live mostly in the southern part of the country, and Muslims, who live mostly in the north. A minority of the population practise religions indigenous to Nigeria, such as those native to the Igbo and Yoruba ethnicities.
As of 2015, Nigeria is the world's 20th largest economy, worth more than $500 billion and $1 trillion in terms of nominal GDP and purchasing power parity respectively. It overtook South Africa to become Africa's largest economy in 2014. The 2013 debt-to-GDP ratio was 11 percent. Nigeria is considered to be an emerging market by the World Bank; it has been identified as a regional power on the African continent, a middle power in international affairs, and has also been identified as an emerging global power. However, it currently has a "low" Human Development Index, ranking 152nd in the world. Nigeria is a member of the MINT group of countries, which are widely seen as the globe's next "BRIC-like" economies. It is also listed among the "Next Eleven" economies set to become among the biggest in the world. Nigeria is a founding member of the African Union and a member of many other international organizations, including the United Nations, the Commonwealth of Nations and OPEC.
The name Nigeria was taken from the Niger River running through the country. This name was coined in the late 19th century by British journalist Flora Shaw, who later married Lord Lugard, a British colonial administrator. The origin of the name Niger, which originally applied only to the middle reaches of the Niger River, is uncertain. The word is likely an alteration of the Tuareg name egerew n-igerewen used by inhabitants along the middle reaches of the river around Timbuktu prior to 19th-century European colonialism.
The Nok civilisation of Northern Nigeria flourished between 500 BC and AD 200, producing life-sized terracotta figures that are some of the earliest known sculptures in Sub-Saharan Africa. Further north, the cities Kano and Katsina have a recorded history dating to around 999 AD. Hausa kingdoms and the Kanem–Bornu Empire prospered as trade posts between North and West Africa.