How highways wrecked American cities
Sometimes I think about how American cities would probably look a lot like closely-knit European cities if it weren't for the idea of demolishing entire city blocks and neighborhoods just to build a highway over it. If you think of any neighborhood near you that's built underneath or around a highway/freeway, you might see some of the ill-effects of highway projects with your very own eyes. These giant concrete structures tend to lend themselves to low property value (pollution and noise are huge factors) and even an increase in crime as it becomes a way for criminals to quickly and easily get in and out of a neighborhood with speed (in fact, a recent book I read talks about how highways can lead to an increase in bank robberies).
If you liked this video above about highways, you might enjoy this Bowery Boys podcast about how Jane Jacobs organized people to save the Village in NYC.