Although the concept first originated in the 17th century, it was the early 1900s when the first commercial air conditioner was made available. Although they're bad for the environment, and rarely needed in the UK, they are totally wonderful in hotter countries. I'm a big fan (sorry) of them, but obviously wish that someone would invent a more environmentally friendly version. These photographs have been taken around the world, but mainly, and obviously, the hotter countries !!