In Toronto, one company estimates that there are 700 million pieces of it strewn about the city.
It's the chewing gum that careless people have spat out without thinking about what will happen to it, or how it could affect the environment.
The issue caught the eye of filmmaker Andrew Nisker, who has travelled the world looking down and documenting how cities deal with all that gum.
His documentary is entitled Dark Side of the Chew.
"Once we get people to see how bad the situation is, then we can get people to start thinking about — well, maybe I shouldn't be throwing that gum on the ground, it's affecting the environment, I should be disposing of that properly," Nisker told CBC News.
Click on the video above to see a full report from the CBC's Philip Lee-Shanok.