Millions of Canadians gathered at Remembrance Day ceremonies across Canada Tuesday to honour the brave men and women who "so selflessly defended our freedom."

In Ottawa, more than 50,000 people gathered at the National War Memorial under a bright sun for the annual Remembrance Day ceremony, and to watch the monument be rededicated by Princess Anne.

Her grandfather, King George VI, dedicated the memorial 75 years ago.

"Today it is fitting that, with this ceremony of rededication, we pay tribute to all Canadians who in the intervening years have laid down their lives in the service of peace, justice and freedom," the Princess Royal said.

Tributes to the Afghanistan mission and the war in South Africa will be added to the monument, as will the new inscription: "In Service to Canada – Au service du Canada."

This year's attendance numbers well well above the norm, police said.

The mood was sombre at the Memorial, which was the site of a horrifying attack on one of two soldiers performing sentry duty there nearly three weeks ago. Cpl. Nathan Cirillo, a reservist from Hamilton, Ont., died in that attack.

Just days before, Warrant Officer Patrice Vincent was killed in a targeted hit-and-run in Quebec.

In a speech upon her arrival at Rideau Hall on Monday, Princess Anne paid tribute to Cirillo and Vincent, and spoke of her personal connection.

"As we stand on the verge of the monument's rededication, I am mindful of this continuum of history and the privilege given us as members of the Canadian Royal Family to share such important moments with you all," she said.

Princess Anne attended the ceremony at the National War Memorial alongside Gov.-Gen. David Johnston and Prime Minister Stephen Harper.

Harper cut short his time at the APEC Summit in China to be back in Ottawa for Remembrance Day in the wake of the attack at the monument and on Parliament Hill weeks ago.

In a brief speech, Johnston also paid tribute to Cirillo and Vincent, noting thatin the attacks that took their lives, "the very symbols of our peace and freedom were violated.

"And now here we stand, and here we shall remain: unshaken in resolve; grateful in remembrance of those who have sacrificed; rededicated, like this memorial, to our eternal duty: peace and freedom -- the very soul of our nation."

Harper noted in a statement that "it is our duty to remember the Canadians who so selflessly defended our freedom."

Hundreds of thousands of Canadians "have earned enormous respect" by answering the call to fight tyranny around the world, he said.

“We can never repay the debt we owe to the intrepid men and women who paid for our freedom with their lives, but we can remember their enormous sacrifices and pay tribute to their bravery and patriotism."

Nov. 11 ceremonies this year mark two significant historical milestones: 100 years since the start of the First World War and 75 years since the start of the Second World War.

Canadians are in active combat too, with jets flying combat missions in Iraq.

According to a new poll conducted on behalf of the Vimy Foundation, more than a quarter of Canadians (27 per cent) said they planned to attend an official commemorative service this year.

The ceremony was expected to draw as many as 80,000 visitors.

Even though most Canadians won't be attending an official service, according to the Vimy Foundation poll, nearly eight in 10 (77 per cent) said they would observe two minutes of silence at 11:00 a.m. on Remembrance Day. Another 77 per cent said they were wearing a poppy in the days leading up to Nov. 11.