Gov. Gen. Michaëlle Jean speaks at Tuesday's Canada Day ceremony on Parliment Hill in Ottawa. (CBC)

Tens of thousands of revellers converged on Parliament Hill on Tuesday to wish Canada a happy 141st birthday.

"There are more reasons than ever to celebrate our country," Prime Minister Stephen Harper told the cheering Ottawa crowd, many of them wearing red and white and waving Canadian flags.

Harper reminded the assembled that Canada is blessed with resources, a vast northern frontier and a diverse population that includes aboriginal people and immigrants from around the world. He said Canadians should be proud of their work to protect the environment and to help Afghanistan.

He noted that this year marks not only the 141st anniversary of Confederation, on July 1, 1867, but the 400th anniversary of the founding of Quebec City, the 150th anniversary of the founding of British Columbia and the 250th anniversary of the establishment of representative government in Nova Scotia, the first democracy in what is now Canada.

"Every day, in countless ways, we are working together to achieve the greatness our country deserves. That's why on this Canada Day, we are prouder than ever to call ourselves Canadians," Harper said.

The festivities got underway earlier in the morning in Ottawa with a historic military parade through downtown streets. The party continued throughout the day with concerts on Parliament Hill, including a performance by Canadian band Blue Rodeo. A massive fireworks display capped off the celebrations in the evening.

Jean praises aboriginal apology

Gov. Gen. Michaëlle Jean attended the Ottawa celebration, speaking on how far Canada has come. Both she and Harper mentioned last month's historic apology to Canada's aboriginal people for the abuse many suffered in the country's residential schools. Jean said the June 11 apology in the House of Commons was long overdue.

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

Festivities overseas, across Canada

Parades and celebrations were held elsewhere across the country and around the world, including a large concert at London's Trafalgar Square.

In Afghanistan, soldiers celebrated with cake and even beer, with soldiers allowed two drinks each. They were treated to a comedy show by Canadian Mike MacDonald, a concert by Canadian country singer George Canyon, and they touched the Grey Cup, which was escorted to the war-torn country by members of the Saskatchewan Roughriders.

Canada Day festivities were organized across Quebec, where it was also annual moving day. Leases in Quebec have started on July 1 for about the last 30 years, since 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 take in the annual Canada Day parade, which wound through Montreal's downtown earlier in the day.

In Quebec City, 400 new Canadians were 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.

In Vancouver, some celebrated 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.

With files from the Canadian Press