Can my iPhone tell me where I have recently been walking?

Option 1 - Google Maps Location History

One of the easiest solutions for background location tracking that takes very low amount of energy. Download Google Maps and Enable "Location History".

How to Enable Google Maps Location History

1. Open Google Maps
2. Tap Menu and then Settings
3. Click Personal content and then scroll down to "Location settings"
4. Click to Turn "Location Services is on."
5. Set Location Services is set to Always with iOS Settings.

You can later view your visited locations at google.com/maps/timeline or on Google Maps "Timeline" tab.

Option 2 - Apple Frequent Location History

iOS has a feature called frequent locations built it's system. Apple provides you with lesser location history and detail. To access the information:

Go to the "Settings" > Privacy > Location Services > System Services > Frequent Locations.

You will find some of the frequent locations you have visited if it's already been turned ON.

Option 3

As mentioned by Owlsnipes in the comment, Moves(acquired by Facebook) is an activity tracker which runs in the background which can record all the movements and classify it as running,walking and driving. It's a pretty neat app and I've used it myself in the past.