Did you know OS X Mountain Lion has 43 secret wallpapers? Each wallpaper is a 3200×2000 resolution, here’s how to find them:
From Finder, hit Command+Shift+G to summon Go To Folder and copy paste the folder path below.
/System/Library/Frameworks/ScreenSaver.Framework/Versions/A/Resources/Default Collections/Here you can browse the hidden wallpapers and set them as your current wallpaper if you wish. The categories of the wallpapers are as follows National Geographic, Aerial, Cosmos , and Nature Patterns. Below is a video showing off this quick tip.