Millions of Germans are casting their votes in the country's federal elections, with Chancellor Angela Merkel tipped to retain power.
She is seeking a fourth term in office and to keep her conservative CDU/CSU alliance's status as the largest presence in Germany's parliament.
Its coalition partner, the social democratic SPD, is its main rival, while the right-wing AfD is likely to gain its first parliamentary seats.
Voter turnout looks set to be moderate.
By 14:00 local time (12:00 GMT) 41.1% of registered voters had cast their ballot, compared to 41.4% by the same time in the federal elections four years ago, according to Germany's federal returning officer.
Mrs Merkel cast her vote at a polling station in Berlin; the SPD's candidate for chancellor, Martin Schulz, voted earlier in the day in his home town Wuerselen in western Germany.
Polling stations opened at 08:00 and close at 18:00, with exit polls expected shortly after.
Image copyright Reuters
Image caption Angela Merkel has been Germany's chancellor since 2005
Image copyright Reuters
Image caption SPD leader Martin Schulz is a veteran of the European Parliament
The election is seen as important because it may result in six parties in the Bundestag - the German national parliament - for the first time since World War Two.
Such a result could mean a change in the makeup of the current governing coalition.
Uncertainty about what a new coalition government could look like was expected to draw high numbers of voters to the ballot boxes, with postal voting higher than usual.
German election: Why this vote matters
Election marks shift in German politics
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Image caption Martin Schulz and Angela Merkel are the main contenders
Angela Merkel: Widely expected to retain her seat, Mrs Merkel is seen internationally as a source of stability - having led Germany since 2005. Her decision to open Germany to asylum seekers during the peak of Europe's migrant crisis cost her politically, but she appears to have recovered
Martin Schulz: The SPD leader was until recently speaker of the European Parliament. Mrs Merkel's main rival is also her coalition partner - which has proved troublesome during the campaign, as he sought to criticise her politics
Alice Weidel and Alexander Gauland: The top candidates for the AfD. Achieving seats in the Bundestag - or potentially becoming the third-largest party, as some campaign polls suggested - would be a major victory
Angela Merkel's quiet power
What does Alternative for Germany (AfD) want?
What are the coalition options?
The SPD's Mr Schulz has already appeared to reject the idea of another CDU-led grand coalition, so what are the realistic alternatives for Mrs Merkel?
A "Jamaica" coalition is seen as increasingly likely: so-called because of the colours of Jamaica's flag - with the black CDU/CSU, the yellow, business-friendly FDP and the Greens. Not a marriage made in heaven, as the Greens want to phase out 20 coal-fired power plants and the FDP disagree. But there is a prototype coalition that has just begun in the northern state of Schleswig-Holstein
A Black-Yellow coalition of the CDU/CSU and FDP. Preferable for Mrs Merkel but the numbers in the Bundestag may not add up. A black-yellow coalition governed Germany from 2009 before the FDP's utter wipe-out in the 2013 election
Another "Black-Red" alliance, of CDU/CSU and SPD, which governed Germany from 2005-2009 and then again from 2013-17. A realistic option in terms of numbers, but many in the SPD would be opposed