Are heat waves simply natural disasters over which we have no control? With heat waves set to increase over the coming decades, how can we fight this invisible killer? In this case study, head back to 1995 Chicago, when one of the deadliest heat waves in US history struck the city, killing hundreds. Learn about the demographics that were particularly vulnerable to the heat wave, and how those vulnerabilities made this heat wave (and others like it) not just a natural disaster, but a social one. After reading this case study and an interview transcript with one of the experts on the 1995 Chicago heat wave, turn to the Discussion Questions to think about how social networks and the built environment can protect us during heat waves now and in the future.