The ultimate rooftop-hopping guide to the world’s summeriest cities

Some cities are best seen from the street level. But in summer, when the weather’s nice and the sunsets are stunning, it’s a bird’s eye view you’re looking for. The trick isn’t always a rooftop bar with a cover charge; sometimes, it’s a glass-floored observation deck, a slow-revolving restaurant, or a hill that looks down on the whole skyline.