“The Slash”

https://commons.wikimedia.org/wiki/File:49_parallel_waterton.jpg
Image: Wikimedia Commons

In areas of mountainous terrain and wildnerness, the border between the United States and Canada is kept clear of brush and vegetation to a width of 6 meters, forming a visible line between the nations that’s visible in satellite images.

The deforested segments total more than 2,000 kilometers.