Nigeria
In short
Nigeria is a large country located in West Africa, bordered by the Gulf of Guinea to the south. It is the most populous nation on the African continent.
In plain words
It is a big country with many different groups of people living together. It has many states and its main capital city is Abuja, though Lagos is the biggest city.
A simple example
A person travelling from Benin in the west to Cameroon in the east would have to pass through Nigeria.
Why it matters
As the most populous country in Africa, its economy and politics greatly influence the rest of the continent. It is also a major hub for culture and film in Africa.
Easy to mix up
Do not confuse Nigeria with Niger, which is a separate landlocked country located to its north.