Apparently your iPhone and iPad stores a hidden, unencrypted, file on the device and backs it up to your Mac — in this file is location data on where you have been. This is both surprising and not that surprising all at the same time, some clever guys did this:

This open-source application maps the information that your iPhone is recording about your movements. It doesn’t record anything itself, it only displays files that are already hidden on your computer.

Posted by Ben Brooks