Construction crews have been working the new Champlain Bridge for about a year now, and the mild winter this year has allowed the 400 workers to stay on schedule.

"The biggest challenge of this project is the demanding timeline," said Daniel Genest, a spokesman for the Signature on the Saint-Laurent Consortium.

The new bridge, which is expected to cost $4.23 billion and have a lifespan of 125 years, is slated for completion by Dec. 1, 2018. 

On Friday, members of the media were invited onto the site. CBC reporter Sean Henry went along for the tour.

To learn more, check out the video for Sean Henry's full report.