Mike Adenuga

Adenuga, Nigeria's second richest man, built his fortune in telecom and oil production.

His mobile phone network, Globacom, is the third largest operator in Nigeria, with 55 million subscribers.

His oil exploration outfit, Conoil Producing, operates 6 oil blocks in the Niger Delta.

Adenuga got an MBA at Pace University in New York, supporting himself as a student by working as a taxi driver.

He made his first million at age 26 selling lace and distributing soft drinks.