Often when we think about lethal heat, we picture things like forest fires. But the fact is, one of the most dangerous places to be during a heat wave is inside a city. And considering that nearly three-quarters of Canadians live in urban areas, that's a big problem — and one that will only get more dangerous with time. Today, CBC Montreal reporter Jaela Bernstien breaks down what "urban heat islands" are, and who is most vulnerable to their deadly impacts. But this story isn't all doom and gloom. There are also lots of ways to fight urban heat — even some that are cheap and quick — and we'll be looking at those too.