Construction has begun in Calgary on what will soon be the tallest structure in Western Canada. 

Mayor Naheed Nenshi was at the groundbreaking on Wednesday for Brookfield Place Calgary, which will rise 56 storeys above the downtown core. 

It's across from the Bay building, facing the seventh avenue C-Train line.

"We actually think this is the best block in Canada," Nenshi said. "Where do you get a full city block, right on the transit line, in the heart of downtown anywhere in the country? And they said because it's the best block in Canada, we want to challenge ourselves to do something spectacular."

The location will include two office towers of more than two million square feet. It will feature restaurants, retail shops and a half-acre public plaza.

Construction on the first tower is set to be complete by 2017.