Not just cities - towns and villages too.

This is to get aid to the person before the ambulance can get there - the 999 (UK emergency service phone number) operator will talk you through where to find one and how to use it. For cardiac arrest, time is vital - the quicker someone can get help, the better the outcome.

They started having defibs at places like sports centres because of several instances of undiagnosed heart conditions causing cardiac arrest in young athletes, and have branched out from there.