You've probably been inside one, and maybe without giving it much thought. But there are roughly 900 so-called centennial buildings still standing that were constructed in each province and territory during the 1960s to celebrate Canada's 100th birthday.

And with the nation's 150th coming up next year, many of those buildings are approaching 50 years old — a lasting legacy, but also buildings that are, or soon may be, in need of renovation.

Ryerson University's Colin Ripley and Marco Polo

Ryerson University architecture professors Colin Ripley and Marco Polo are the co-authors of Architecture and National Identity: The Centennial Projects 50 Years On. (CBC)

"Many people don't realize that when something is called 'Centennial this' or 'Centennial that,' that it is a product of this explicit program," said Colin Ripley.

The Ryerson University architecture professor co-wrote Architecture and National Identity: The Centennial Projects 50 Years On, a companion book to an exhibit on centennial projects that opened at Charlottetown's Confederation Centre of the Arts in 2014, and also ran last year at the National Arts Centre in Ottawa.

"I have to say that in terms of forming Canada, in terms of what Canada is today, it's had a really big role."

860 buildings nationwide

There are approximately 860 buildings across the country that were constructed as centennial projects. The plan to provide funding for the structures was announced by then-prime minister John Diefenbaker in 1961.

By 1964, the federal government had earmarked approximately $100 million — about $743.6 million in 2012 dollars, according to a Parliamentary report — for centennial-related projects.

Centennial Concert Hall

Winnipeg's Centennial Concert Hall, one of the nearly 900 centennial buildings constructed in the 1960s. Many, like the Concert Hall, were built in the brutalist style. (Tourism Winnipeg)

Ripley says it was the direct result of the Massey Commission, completed a decade earlier, which urged the forging of a Canadian identity through more federal support for arts and culture.

Each province and territory received funding for one marquee structure, and every municipality got money too — a dollar for each citizen.

It resulted in some unique projects, like a UFO landing pad in St. Paul, Alta., and Sudbury's Big Nickel.

But Ripley said the centennial funding also resulted in so many buildings people often take them for granted, although he said they represented a major step in national unity at the time.

Exercise in nation building

"Up until that point we had an English identity, we had a French-Canadian identity, distinct regional identities," he said. 

"This was an attempt, explicit, to find out what it was to be Canadian."

The first building constructed under the centennial program was the Fathers of Confederation Memorial Building in Charlottetown — now called the Confederation Centre of the Arts.

Its exterior is smooth sandstone with few windows, stark and unapologetically modern for the time.

"Within architectural circles one would call them, for the most part, brutalist," Ripley said of the centennial buildings.

Confederation Centre of the Arts

The first building constructed under the centennial program was the Fathers of Confederation Memorial Building in Charlottetown — now called the Confederation Centre of the Arts. (TourismPEI)

The National Arts Centre in Ottawa, another centennial building project, is also a prime example of the brutalist style. So too are centennial projects like the Ontario Science Centre, the Arts and Culture Centre in St. John's, N.L., and the Centennial Concert Hall in Winnipeg.

For the most part, all of the marquee centennial projects remain vital venues in their communities, according to Ripley.

Culture flourished, but national unity elusive

And so in one sense, Diefenbaker's dream came true — arts and culture flourished. But national unity was more elusive, Ripley said.

He notes that right around the peak of the October Crisis in 1970, the National Arts Centre in Ottawa was completed, and  Pierre Trudeau attended its opening — while the nation was transfixed by insurrection.

And then a year later, the last of the centennial buildings was completed — Le Grand Théâtre de Quebec.

"Certainly by the time that building opened, there was very little appetite for centennial celebrations in Quebec," according to Marco Polo. He's also a professor of architecture at Ryerson, and Ripley's co-author on  Architecture and National Identity.

"So literally, by the time the whole project came to completion, the whole national unity project was in serious trouble."

Some buildings in need of renovation

Polo also said tastes in architecture changed, and for several decades afterward the brutalist style was considered by many to be ugly.

But now, 50 years later, he says brutalism is back — and many of his students love it.

National Arts Centre Diamond Schmitt Architects.

As centennial buildings age, some are undergoing extensive renovations. This rendering shows planned changes to Ottawa's National Arts Centre, expected to be finished in time for Canada's 150th birthday. (Diamond Schmitt Architects)

But he and Ripley also said in general, modernizing brutalist buildings can be a challenge — a concern as many of the centennial buildings approach their 50th birthdays.

The Royal Alberta Museum, for example, is moving venues — and Ripley and Polo said there's a question mark over the centnnial building's future.

But they also said they're eager to see how the current refurbishment of the National Arts Centre in Ottawa will turn out — a project set to be complete by July 1, 2017, just in time for Canada's 150th.