Look up, look waaaay up!
Workers with a company called Industrial Chimney Maintenance are performing routine maintenance on the nickel mining giant Vale's "Superstack" in Copper Cliff.
According to Vale, the work is to maintain the integrity of the structure.
Sudbury's local science centre says the Superstack measures 381 metres or 1,250 feet high, 35 metres wide at the base, and 16 metres wide at the top.
It is the second tallest chimney in the world, exceeded only by a power station chimney in Kazakhstan.
The Superstack also has the distinction of being the second tallest structure of any type in Canada, ranking behind Toronto’s CN Tower. When it was completed in 1972, it held the record of being the tallest structure in the world.
In the following video, Radio-Canada videographer Yvon Theriault shows the heights the workers must reach to get the job done: