Skyscanner is a global leader in travel originally from UK that now serves millions of people across the world through their on-line website. They have come up with this list of cities while suggesting the average person has not visited 15 cities on this list.
So I decided to put that assumption to test and what better place than List Challenges itself. I am willing to bet that the users on this site will average more than 15 entries.
Let's find out!