2010 GDP: $194 billion
2010 FDI: $6.1 billion
Nigeria is Africa's largest oil producer, therefore a big draw for some of the world's biggest energy and resources companies.
Political unrest and growing ethnic and religious tensions make the country one of the worst places to do business in, however. Nigeria ranks among the lowest in the world when it comes to getting electricity and registering property for business. It takes nearly three months to get through the 13 procedures required to register a property, compared to one month in OECD countries.
The oil trade has also fueled violence and corruption in the Niger delta, where energy giants, including Royal Dutch Shell, have been forced to shut down production often due to a surge in oil thefts.
Despite being an oil-rich country, the majority of its population live on less than $2 a day and are exposed to dangerous levels of pollution. Nigeria's political instability reached a head last year, when its then-president Umaru Musa Yar'Adua left the country for medical treatment without transferring power, creating a leaderless state for two and half months before an acting president was reinstated.