Scotland voted Thursday in an independence referendum that could break up the centuries-old United Kingdom and create Europe's newest country since the collapse of Yugoslavia.
Some 97 percent of eligible Scots -- nearly 4.3 million people -- have registered to vote, underscoring the passions that the historic decision has ignited across the country.
In queues snaking outside polling stations, voters spoke emotionally about the momentous choice they were faced with -- what one voter called "a wonderful democratic process".
"It's an important day. This is a decision which lasts forever, which will impact my children," said Charlotte Farish, 34, who turned out to vote early in Edinburgh with her two children before taking them to school and heading into work.
Sitting on a bench in the city centre of Glasgow, reading a newspaper after casting his ballot, James Hawkin, 64, said: "I think the result will be tight".
After months when it looked like the independence camp could not win, a surge in support in the final two weeks has left pollsters warning the outcome too close to call.
One of Scotland's most famous sportsmen, tennis star Andy Murray, appeared to lend his support to separation in a last-minute tweet accusing the "No" campaign of negativity.
"Let's do this!" Murray, who no longer lives in Scotland, tweeted, echoing a slogan raised by pro-independence First Minister Alex Salmond in a final fiery campaign speech.
British newspapers quickly made the statement a top story and 12,000 people re-tweeted the message, including Salmond.
"We can take our future into our own hands," Salmond told AFP after voting in the village of Strichen in a farming region in northeast Scotland where he is the local lawmaker.
"We've got the chance to build a more prosperous economy but also a fairer society," he said.
British Prime Minister David Cameron has pleaded with Scots to vote in favor of keeping "our home" and has warned the break-up would be a "painful divorce" full of economic risks.
If Scots vote "Yes", it would end a union dating back to 1707, could force Cameron to resign and might raise serious questions about Britain's status on the international stage.
Financial markets have been volatile for days on uncertainty over the outcome, which is being watched closely around the world.
The force of the "Yes" campaign has encouraged separatist movements, such as Catalans in Spain, while a number of Britain's allies have urged the Scots not to leave.
"I hope it remains strong, robust and united," US President Barack Obama said in a tweet from his official account.
The question for voters at Scotland's more than 5,000 polling stations is "Should Scotland be an independent country?" and they are asked to mark either "Yes" or "No".
Polls close at 2100 GMT and the result is expected in the early hours of Friday morning.
From the windows of people's homes to stands on street corners, lapel badges and even cupcakes, support for the "Yes" campaign has been more visible than for "No" in many parts of Scotland.
But the "No" camp insists that many voters opposed to independence have simply not made their voices heard yet.
"The silent majority will be silent no more. We will not have this," said Britain's former prime minister Gordon Brown, who is Scottish, in a passionate appeal to a Glasgow rally on the final day of campaigning.
The final opinion polls put the "No" camp slightly ahead, but there remain many undecided voters whose decision will be crucial.
"I'm going to be looking at what side makes the better argument, whether I can believe one side," said Steven Andrew in Scotland's capital, Edinburgh.
Debate in the campaign has focused on the economy, including what currency an independent Scotland would use and whether its North Sea oil wealth would help make it a richer nation.
Questions over whether an independent Scotland could be a member of the European Union and how long this would take to negotiate have also surfaced repeatedly.
Scotland's Parliament, opened in 1999, holds some powers devolved from Westminster to set policy in certain areas of domestic policy, such as health and education.
Even if there is a "No" vote, Scotland is set to be handed new authority over areas like tax and welfare, which Brown says could amount to effective home rule.
But a detailed timetable for this only emerged late in the campaign after Brown effectively stepped in to take control of the "No" camp after it looked like it might lose.
"The status quo is gone," Cameron said in his final campaign speech on Monday in Scotland. "There is no going back to the way things were. A vote for 'No' means real change."