Canadian voters are going to the polls to decide whether to extend Conservative leader Stephen Harper's near-decade in power or return Canada to its more liberal roots.
Prime Minister Mr Harper is trailing Liberal leader Justin Trudeau, the son of late Prime Minister Pierre Trudeau, in the polls.
Pierre Trudeau led Canada for almost all of a 16-year stretch from 1968-84. He is responsible for the country's version of the bill of rights and open door to immigration.
Mr Harper is seeking a rare fourth term.
"We have a chance to bring real change to Canada and bring an end to the Harper decade," Mr Trudeau said in Mr Harper's adopted home province of Alberta, traditionally a Conservative stronghold.
Mr Trudeau, 43, ran an optimistic campaign and appears to have overcome relentless attack ads. In the final days of the campaign he visited districts where the Liberals traditionally have not won but now have a chance to.
Mr Harper, 56, ran a divisive campaign that played on fears of the Muslim face veil. He visited districts he won in the 2011 election in an attempt to hang onto them.
The Liberals lead the Conservatives by almost 9 percentage points. According to the CTV/Globe and Mail/Nanos Nightly Tracking Poll, the Liberals are at 39.1%, followed by the Conservatives at 30.5%. The New Democrats are at 19.7%. The margin of error for the survey of 800 respondents is 3.7 percentage points.
A minority government in the 338-seat Parliament appears likely no matter which party wins the most seats. That would mean the winning party would have a shaky hold on power and need to rely on another party to pass legislation. Mr Harper has said he will step down as Conservative leader if his party loses.
If the Liberals win the most seats they are expected to rely on the New Democrats for support on a bill-by-bill basis. If Mr Harper's Conservatives win the most seats, the Liberals and New Democrats say they will defeat them in a vote in Parliament, raising the possibility of a coalition government or arrangement.
"It's hard for me to see a path for his survival now," said Tom Flanagan, Mr Harper's former campaign manager. "When you play out all the scenarios they all seem to end with a defeat on election night or a very tenuous victory that would not allow Harper to survive very long."
If he wins, Mr Trudeau, a former teacher, would become the second youngest prime minister in Canada's history.
David Axelrod, who helped mastermind Barack Obama's 2008 campaign and offered advice to Mr Trudeau's team, tweeted congratulations to Mr Trudeau's top advisers and said "Hope beats fear".