The first time I saw one, it was displaying a demo of the neon lit Vegas strip at night. It really felt like looking out of a 3rd story hotel room. If I had just woken up in a room with just that view, I would have totally believed I was there.

It was enough of a magical experience that I sought one out as soon as I could. Now, where do I find more 4K HDR content like that..

(oh, you are probably referring to app windows.. nvm)