What Does Apple Have on You - Go Here

Apple has launched a privacy website that allows you to download all the information Apple has on you that is stored on their servers. 

Go to privacy.apple.com. This is where you'll choose exactly what you want to download. You can select certain things that might be important, like your App Store activity or all the notes you've stored in iCloud. If there are items you don't use, then you don't have to check them.

At the bottom of the page you'll see a list of files that might be large, like your entire iCloud photo library.