If you own an iPhone, you're probably aware of Location Services, which gives apps access to your real-world location. It's how Apple Maps and Google Maps are able to give you directions and learn where you live and work to give you notifications as you are heading out.
But what you probably didn't know is your iPhone keeps track of a list of all of your real-world movements, whether or not you are using apps that are using the GPS antenna built in to your phone.
It's called "Significant Locations" and it's hidden deep in iPhone settings. Apple says the list is used to "allow your iPhone to learn places significant to you in order to provide useful location-related information in Maps, Calendar, Photos and more."
Apple also claims that they are not accessing this information from you and that "Significant Locations are encrypted and cannot be read by Apple." Still, it's disconcerting that the feature is turned on by default when you enable Location Services during an initial iPhone setup. Also the fact that Apple says "and more" means there could be other apps that are using the information.
To find it, go to Settings, then Privacy, then Location Services, then scroll to the bottom and press System Services, then scroll down to find Significant Locations and the list.
First, go to Privacy:
Then, go to Location Services:
Scroll all of the way down to System Services:
Then find Significant Locations near the bottom: