The year is 2018. Cities are hot. Really, really hot. Thanks to something called the “urban heat island effect,” cities like Los Angeles and New York are literally the hottest places to live — and climate change is only warming things up more.

An epic heat wave wreaked havoc across L.A. this past week, leaving more than 26,000 residents without power after temperatures spiked to 109 degrees downtown. The good news is that cities are taking action to stem the serious public health threats that come along with extreme heat. If you want to read more about New York’s efforts to stay cool, check out this week’s cover story.