It “has changed buildings, and the ways they are used, more than any other invention: more than reinforced concrete, plate glass, safety elevators or steel frames. Its effects have directed the locations and shapes of cities.” What is it? Here are some more hints: We’ve “reached the point where a ski-slope with ‘real’ snow could be built in a Dubai shopping mall” and the 2022 World Cup is being held in Qatar. In The Guardian, Rowan Moore takes an interesting look at an inversion of nature: how air conditioning created the modern city. As your air conditioner keeps you cool inside, it makes it just a tiny bit hotter outside. That’s worth keeping in mind as the world continues to heat up.