Leonhard Foeger/Reuters
The Austrian presidential election sees independent candidate Alexander Van der Bellen go head-to-head with Norbert Hofer, who leads the far-right party the Freedom Party Of Austria.
It is Austria's second attempt to elect a new president this year.
Van der Bellen defeated Hofer in May but the result was nullified after alleged irregular vote counting across the country. The May election separated the pair by a tiny margin of just 0.6% - Van der Bellen picked up 50.3% of the popular vote, while Hofer received 49.7%.
This election is also a prime example of how polarised and unpredictable politics in many western countries is right now, with two candidates from opposite ends of the conventional political spectrum vying for the presidency and the "middle-ground" nowhere to be seen.
Hofer is described as Austria's answer to Donald Trump. He has pledged a huge crackdown on immigration at a time when high levels of migration into the EU from the Middle East have left many Austrians feeling anxious and insecure.
His anti-immigration stance does not stop at policy. He has a number of contentious claims to his name - like when he suggested that rising gun ownership in Austria is linked to the growing threat posed by migrants. "In uncertain times, people try to protect themselves," he said. He even carried a pistol with him on the campaign trail.
On the other hand, you have radical environmentalist Van der Bellen, who could not be further away from his opponent's politics. The former Green Party leader supports socially liberal policies like equal marriage rights in a country with a long conservative Catholic tradition. He is pro-EU and backs a federal Europe.
If Hofer wins, it will give yet more credence to the notion that populism is on the march across the west.
Not only would it come just weeks after the shock victory of Trump over Hillary Clinton, but it would be seen as paving the way for right-wingers elsewhere in the continent to win upcoming elections, like Marine Le Pen in France.
A result is expected in the early hours of Monday morning.