The Same Sky Phenomenon

Vintage postcards are available for locations all over the world, but somehow, they all have the same sky. Or one of three skies, it seems, with recognizable cloud formations if you keep an eye out for them. Vox takes a deep dive into them with James Brouwer, a postcard collector who found this phenomenon in his massive collection. Yes, there is an explanation. We'll learn a lot of about tourism postcards in the process. As soon as I finished watching the video, I went to my envelope of postcards. They aren't vintage, just family souvenirs. Most don't even have clouds, and I saw no duplicates. (via Nag on the Lake)