With heatwaves breaking records around the world, urban planners and local officials are coming up with solutions to keep sweltering cities cooler, and save lives.

The heatwaves aren't here yet. But they will come.

Extreme heat has been the greatest weather-related cause of death in the U.S. for the past 30 years — killing over 700 people per year.

Vegetation-covered roofs may be challenging to create and maintain, but they can be up to 40 degrees cooler than conventional roofs. They can also reduce flash flooding and provide islands of habitat for pollinators.