OTTAWA -- It is one of the largest, longest, and most expensive renovations in Canada, to refurbish and preserve our heritage in the Centre Block of Parliament Hill.

It is Canada's most iconic building and, for more than a century, Parliament Hill has been the cornerstone of our democracy.

Rob Wright, Assistant Deputy Minister of Science and Parliamentary Infrastructure with Public Services and Procurement Canada, says the building is part of our country's history and the stories are carved into the stone embedded in the walls. 

Centre Block's massive renovation will cost nearly $1 billion. When completed, the building will be carbon neutral, and be ready for the digital age. 

"When Canadians come back into the Centre Block, they're going to recognize it, but it's going to operate as a modern facility," Wright says. 

It will also be universally accessible. The construction endeavour will add elevators in outdoor courtyards, which will be converted to indoor common space. 

A major challenge is balancing the restoration while preserving its history, which predates Canada. Construction of Parliament began in 1859 and, in 1916, the Great Fire destroyed all but the library. It took 10 years to rebuild, and will likely take just as long to renovate. 

There are more than 400 workers carefully chiselling away at demolition. Many parts of the building will be stripped to the bricks to make way for new heating and ventilation, wiring, and digital infrastructure. 

The hand-painted linen ceiling inside the House of Commons is being carefully removed preserved and will be reinstalled. 

The asbestos hiding beneath it however, has to go. It is all throughout the building and, so far, nearly 2,500,000 kg has been removed. 

There will be areas left untouched, such as the suspended plaster ceiling in the Senate chamber, which is hand-stencilled and covered in gold foil. 

The huge Tyndall stone branches in the rotunda will remain, as will hundreds of other carvings high up in the ceiling.

Dominion Sculptor Phil White says Parliament's architect, John Pearson, left hundreds of untouched stones throughout the complex so that those blocks could be carved in sculpted to interpret Canadian history as it involved. White will create and form some of that new history. 

"It's like you're picking up your predecessors brush are picking up their materials and it's an amazing feeling," he said.

Currently, there are approximately 22,000 heritage elements remaining throughout Centre Block. Many are stone pillars and marble floors and walls, which will be removed, catalogued and shipped off site. 

With the help of a highly detailed digital model, one day they will be reassembled exactly where they once were, in order to continue to tell their story.  

Correction:

A previous version of this story mistakenly referred to Tyndall stone as "kindle stone". We regret the error.