Thanks to 'Nearby Friends' on Facebook
Facebook is constantly altering and add features to its offering. One feature that appeared some time ago is 'Nearby Friends'. This allows you to see where your friends are, at any given time.
This can be found at the bottom of the Facebook menu, where you find 'Friends' and 'events'.
Tapping on the Nearby Friends icon brings up a page like this:
Not only can you see friends in your area, but you can see when they were there and just how far away they are. Friends that log in whilst abroad are identified as 'travelling'.
This is handy for those times when you're early for a meeting or just looking for a friend to grab a coffee with.
You can turn the location tracking off by doing the following:
Facebook > More > Nearby Friends > Settings > Location settings > Turn off location history