Voters have been casting their ballots to choose a new president for Nigeria, with more than 175,000 registered polling stations open across the country.
The votes come as the country struggles with a national bank note shortage that some people fear will result in a lower-than-expected turnout.
In order to win, the next president will need at least 50% of total votes and at least 25% of the vote in two thirds of Nigeria's federal states.
Voting was delayed in some states where electoral officials did not arrive in time to verify the identity of voters before they could cast ballots.
Polling stations were due to close at 2.30pm (1.30pm UK time), but Mahmood Yakubu, head of Nigeria's Independent National Electoral Commission. said everyone would have the opportunity to vote, "no matter how long it takes".
Counting and collating the ballots is expected to take several days and the official results are expected to be announced in the first half of next week.
The country currently has 18 presidential candidates, but only three of them have emerged as front-runners.
Who is taking the lead?
Nigeria's favourites are ruling All Progressives Congress Party candidate and former governor of Lagos, Bola Ahmed Tinubu, and the main opposition candidate Atiku Abubakar.
The third favourite is Peter Obi, candidate of the Labour Party who has been leading in opinion polls.
But whether supporters of these party's would show up in force at the polling stations - remained unclear due to the long waiting hours at banks across the country this past week, in search of money.
Two of the top candidates, Bola Ahmed and Atiku Abubakar, are in their 70s and both have been in Nigerian politics since 1999.
While Peter Obi, 61, is the youngest of the front-runners and has surged in the polls in the weeks leading up to Saturday's vote.
Bola Tinubu has the strong support of the ruling All Progressives Congress party as an important backer of the incumbent president.
Atiku Abubakar is recognised as being one of Nigeria's richest businessmen, while also having served as a vice- president and presidential hopeful in 2019 for his Peoples Democratic Party.
The election has also featured many first time voters.
Wuraola Abulatan in Lagos accused the ruling party of failing to deliver on the promises it made in 2015 when it first came to power.
"I lost hope for Nigeria but when Peter Obi started campaigning, that hope came back," she said.
"I want to see Nigeria get better."
The currency crisis
The full impact of Nigeria's currency crisis on Saturday's election was not immediately clear, though officials said they had been able to get much of the money the government needed to carry out the vote.
In November last year, after the decision to redesign Nigeria's currency, the naira - new bills have been slow to circulate.
Older bank notes also stopped being accepted and created a shortage in the country where many use cash for their daily needs.
The vote is being carefully watched as Nigeria is Africa's largest economy and one of the continent's top oil producers.
According to UN estimates, by 2050, Nigeria will tie with the US as the third most populous nation in the world after India and China.
It is also home to one of the largest youth populations in the world: about 64 million of its 210 million people are between the ages of 18 and 35, with an average age of only 18.