Canada's 141st birthday was celebrated across the country, with face-painting, backyard parties and, in some places, military cannons pounding out ear-splitting 21-gun salutes to mark the occasion.

As a crowd estimated at 75,000 basked under intense sunlight beneath the Peace Tower in Ottawa, Harper spoke of the apology he made last month to aboriginals who suffered abuse decades ago at residential schools, calling it "an important evolution in Canada's relationship with our first peoples."

The June 11 apology was long overdue, but very much needed, the Governor General later told the nationally-broadcast event.

"On that day, all of us together - Inuit, Metis, First Nations and non-aboriginals - joined hands in committing to bridge the gaps entrenched by years of injustice," she said to loud applause.

"The time had come. The time had come."

Harper also told the gathering of the many milestones Canada celebrates in 2008, including the 400th anniversary of the founding of Quebec City and the 250th anniversary of the establishment of representative government in Nova Scotia.

"And the 150th anniversary of the founding of the Crown colony of British Columbia," Harper added, "ensuring our country would stretch from sea to sea."

The national Canada Day celebrations began with a historic military parade through the streets of Ottawa, followed by a formal flag-raising ceremony on Parliament Hill.

Early revellers were also treated to a stirring military drill and the music of the Changing of the Guard ceremony, followed by a performance by the RCMP Musical Ride.

'O Canada' was sung by a choir of Grade 10 students from schools spanning the Ontario-Quebec border. That was followed by a number of performances by a diverse group of entertainers - from Blue Rodeo, to country singer Paul Brandt, to the beating sound of the rhythmic group Drum.

In Halifax, thousands flocked to the city's Citadel Hill to mark the country's birthday.

Inside the historic fort, four-year-old Ryan Yang anxiously waited to hear a booming 21-gun Canada Day salute.

His mother, Yi Xie, said she and her husband immigrated from China seven years ago. She said they've participated in Canada Day events ever since.

"For me, it's a very proud (day) because I can feel that finally that I am Canadian," Yi said. "I really want Ryan to know what the country is like and what people do to celebrate."

Bombardier Michael Hobb, 21, was one of the reservists from the First Field Regiment who fired the ceremonial gun salute.

Hobb said he didn't mind being on duty on Canada Day. It's a far cry from how he spent the holiday last year - in the field while on a seven-month tour of duty in Afghanistan.

He said there wasn't much time or opportunity for celebrations then.

"The best we could do was say 'Well, it's Canada Day,"' Hobb recalled.

Hobb's time overseas gave him a greater appreciation for the freedoms Canadians enjoy, he said. "I've always loved my country ... but it's different now."

Canada Day festivities were organized across Quebec, but many people in that province were kept busy hauling furniture and boxes as the province coped with its annual moving day.

Leases in Quebec have started on July 1 for roughly the last 30 years after a provincial law was passed to synchronize them with the end of the school year.

Still, many Quebecers managed to attend a concert and activities in Montreal's Old Port and to the annual Canada Day parade, which wound through Montreal's downtown earlier in the day.

In Quebec City, 400 new Canadians were also sworn in as citizens, the number coinciding with the city's 400th anniversary. Similar ceremonies took place in other cities, including Toronto where 30 new Canadians were sworn in.

Not everyone in Quebec was extolling Canada's virtues Tuesday. Two groups of sovereigntists held peaceful protests - one in Montreal, the other in Quebec City.

In Vancouver, many were celebrating in a cloud of smoke as about 300 people marked Cannabis Day. The annual event always coincides with Canada Day and draws pot enthusiasts who openly sell, smoke and ingest pot in front of the Vancouver Art Gallery.

Women dressed in fairy wings resembling pot leaves danced through the dense crowd, while hundred slumped on the steps of the gallery in a near vegetative state. Along with pot, there were plenty of baked goods to be bought.

Smoking a joint rolled in papers printed with red maple leaves, Jerome Baker said he was visiting Vancouver for the first time and planned his trip to coincide with Canada Day.

"You won't ever see anything like this in America whatsoever," said Baker, who lives in Atlanta, Ga.

"In the middle of the downtown...people openly smoking marijuana. It's quite possibly one of my most favourite places on earth. I'm considering a relocation here."