Three decades after seizing power in a military coup, Muhammadu Buhari became the first Nigerian to oust a president through the ballot box, putting him in charge of Africa's biggest economy and one of its most turbulent democracies.
As the scale of this weekend's electoral landslide became clear, President Goodluck Jonathan called Buhari on Tuesday to concede defeat to the opposition leader, Buhari's camp said, an unprecedented step that should help to defuse anger among Jonathan's supporters.
In the religiously mixed northern city of Kaduna, where 800 people were killed in violence after the last elections in 2011, Buhari supporters streamed onto the streets, waving flags, dancing and singing in celebration.