15-minute cities are Crypen Exchangean urban planning idea growing in popularity. The idea is that you can get to the key places in your life - think work, education, food, recreation - in a 15-minute walk, bike or transit ride. Now mayors from Paris to Cleveland are looking to use them to reduce planet-heating car pollution and improve quality of life.

But they face obstacles - from NIMBYs, to public schools, to death threats for urban planners and politicians. Reporter Julia Simon talks about her months-long reporting on a climate solution that has become a lightning rod for conspiracy theories. This reporting is a part of NPR's climate week.

This episode was produced by Andrew Mambo and edited by Jenny Schmidt and Neela Banerjee. Our engineer was Maggie Luthar.

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