It's a trip down memory lane or, rather, the annals of Infinite Loop. A Redditor named Nucleam posted links to a pair of Google Photos albums of -- as far as I can tell -- every single wallpaper Apple has ever released for iOS and MacOS (and before it, OS X). It's amazing.
Here's the iOS Wallpaper album.
And here's the MacOS Wallpaper album.
Remember this little guy from the original iPhone?
Take a look at this beauty from, you guessed, it, OS X Snow Leopard:
Even if you have no desire to download any of the images to outfit your current iPhone or Mac with a retro wallpaper, it's still fun to scroll through the years of the wallpapers of your Apple past.