By Aditi Sangal, Fernando Alfonso III, Mike Hayes and Laura Smith-Spark, CNN
The left-leaning Social Democratic Party (SPD) is narrowly ahead in exit polls published after voting ended in Germany’s federal election, a Forschungsgruppe Wahlen exit poll for CNN affiliate n-tv suggests, but the final result of the closely fought contest remains uncertain.
From CNN's Sebastian Shukla
While Berlin’s marathon comes to a close, the country's electoral race is reaching its finish line.
The country will have an idea of where German politics goes next after Angela Merkel at about 6 p.m. local time (12 p.m. ET).
Over at Social Democratic Party headquarters, a short walk down from Checkpoint Charlie, the atmosphere is building slowly.
Audio from German broadcasters has started to fill the air and media from around the world has descended and are jostling into position.
A statue of the former German Chancellor Willy Brandt stands in the building's atrium next to a red platform where current SPD leader Olaf Scholz will appear later today.
From CNN's Stephanie Halasz
The federal elections commissioner says voter turnout by 2 p.m. CET (8 a.m. ET) stood at 36.5%.
By this time on election day four years ago, voter turnout was at 41.1%.
However, it's worth noting that postal votes have not yet been added to today's tally.
CNN spoke to several voters at a Berlin polling station earlier today.
One voter said climate change was a deciding factor when selecting the party they were voting for. When asked if they would miss Angela Merkel, the voter added, "I mean, she stood in a way for stability, but maybe not for progress. And so that's okay that she's retiring now."
Another voter told CNN it was "time for a change."
"I think of course Angela Merkel did also good things in her time. But I think of course there's also some issues or some points that for my opinion, um I would make it different. So I think generally it's good for a change, always the same is not possible to go further," he said.
From CNN's Rob Picheta
German elections to the Bundestag are run on a system of proportional representation, meaning that each party's vote share relates directly to how many seats they get in parliament.
That principle makes it virtually impossible for a party to lead a government alone; coalitions must instead be formed after the vote, and these often contain more than two groups.
Each citizen has two votes: Germans are asked to pick their local lawmaker, and also their preferred overall party. Once the results come in, a race will start to put together enough seats to govern, meaning smaller parties can become kingmakers.
Ben Schreer, from the International Institute for Strategic Studies' (IISS) Berlin-based Europe office, told CNN before the vote: "Whoever wins on paper on Sunday night probably can't be sure that he or she will actually lead the government, because there's going to be so many permutations."
Schreer added: "We may not know until November, if we're lucky."
By CNN's Rob Picheta, Alex Carey and Nadine Schmidt
German politics is dominated by two parties — the center-right Christian Democratic Union (CDU) and the left-leaning Social Democratic Party, or SPD — who have governed together in a coalition for the past eight years.
But other parties have grown in popularity over the past decade as the CDU and SPD have lost ground. This election is particularly close; the CDU and SPD have both held polling advantages, and the Green Party has also emerged as a serious contender.
Here are the candidates:
Armin Laschet: Christian Democratic Union
Merkel's successor at the helm of the CDU is Armin Laschet, 60, a long-time ally of the chancellor and the party's deputy leader since 2012.
A devout Catholic whose father was at one point a coal mining engineer, he was selected as the party's candidate after a torturous leadership tussle.
Laschet has a background in law and journalism, and was elected to the German Bundestag in 1994.
Merkel has voiced her support for Laschet, but despite her efforts to persuade Germans to stick with the CDU, polling suggests her replacement as the party's leader has struggled to win over Germans.
Olaf Scholz: Social Democratic Party
His foremost opponent is the SPD's Olaf Scholz, who has taken a surprise lead in the polls in recent weeks, leaving him as the marginal frontrunner heading into Sunday's vote.
Like Laschet, Scholz has a long history as a political player in Germany. He has been Merkel's finance minister and vice-chancellor since 2018. He previously served as Minister for Labour and Social Affairs between 2007 and 2009. These roles placing him arguably in a better position to run as her natural successor than her own party's candidate.
Scholz has earned increased visibility as he navigated Germany's economic response to the pandemic, and cleared the last electoral hurdle with an assured performance in the final television debate.
The SPD, the oldest political party in Germany, set up in 1863, favors a stronger focus on social issues and wants more taxes for the more affluent individuals in Germany.
Annalena Baerbock: Green Party
The Green Party's leader Annalena Baerbock caused a brief sensation in German politics when she surged in the polls early in the campaign, prompting voters to wonder whether she could become the country's first ever Green chancellor.
The Green Party is now being seen as the potential kingmakers in coalition negotiations.
Christian Lindner: Free Democratic Party
Another party which could be possible kingmakers in coalition talks is the liberalist Free Democratic Party (FDP).
The FDP have never led a German government but have traditionally held influence over the decades, mostly in coalitions with the CDU and the SPD.
Alice Weidel and Tino Chrupalla: Alternative for Deutschland (AfD)
The far-right AfD remains a stubborn presence on the political scene, helmed by Alice Weidel and Tino Chrupalla.
The refugee crisis that sparked the AfD's surge in German politics back in 2015 has subsided as a pressing political issue, but the party remains an outlet for voters angered by immigration issues. In March, they became the first German party since the Nazi era to be put under government surveillance.
It’s currently the third biggest party in the German parliament and the largest opposition party for the past four years.
In 2017, the AFD managed to steal voters from the CDU (those voters unhappy with Merkel’s shift to the center) and from the SPD. However, the party has struggled to keep its momentum going since then and faced harsh criticism over ties to the extreme far-right.
From Alex Carey
Several of the party leaders called on the public to head to polling stations and cast their ballots in the parliamentary elections in Germany on Sunday.
The CDU's Armin Laschet told reporters: “We all feel that this is a very important federal election, an election that decides the direction of Germany in the next few years, and that is why every vote counts, and that is why I hope that everyone will use their right to go to the polls, so that democrats can elect a new government in the end.”
Olaf Scholz, leader of the left-leaning SPD, said he hoped Germans would give him the mandate to become the next chancellor.
"Now I hope that as many citizens as possible will go to the polls and cast their votes and make possible what has become apparent, namely that there will be a very strong result for the SPD. And that the citizens give me the mandate to become the next chancellor of the Federal Republic of Germany," he said.
Meanwhile, Annalena Baerbock, the chancellory candidate for the Green Party, also made some brief remarks after casting her vote in her hometown of Potsdam on Sunday afternoon.
She asked people to cast their votes in order to enter a new era and emphasized the importance of democracy.
"Every vote will count in this election, as we have seen in the last few weeks and how close it will be. Of course, we hope for a few more votes in view of the poll results so that we can create a real new beginning in this country," she said.
By CNN's Rob Picheta, Lauren Said-Moorhouse, Alex Carey and Nadine Schmidt
Germans are voting in a knife-edge parliamentary elections Sunday to find out who will eventually take charge of the country and replace Angela Merkel, who has spent the last 16 years as chancellor.
The race to become Merkel's successor is tight, and the ultimate victor may not be known for days or even weeks after polls close.
Latest polling on Saturday suggested the center-left Social Democrats (SPD) hold a small but narrow lead over Merkel's party, the center-right Christian Democratic Union (CDU).
Why the vote matters: Merkel has been a stabilizing force in Europe since she took on the role in 2005.
The chemist-turned-political mainstay has withstood a wave of populism, a financial crisis, a pandemic and Brexit to carve out an impressive legacy as the world's most successful female leader.
Germany has the largest economy in Europe and the result of this election will matter for European and global economies. Around 60.4 million people aged 18 and above are eligible to vote in Sunday's ballot, according to figures from Germany's Federal Statistics Office.
Key moment to watch for: Poll stations opened at 8 a.m. local (2 a.m. ET) and will close at 6 p.m. local (12 p.m. ET), with exit polls expected almost immediately after.