Every year, around nine billion people are ferried by airplane between various destinations across the planet. And at any given moment, there are roughly 500,000 people in the air, watching clouds and civilization pass beneath.
Airplanes (and the airports they pass through) are designed for endurance. Tens of millions of passengers often find themselves in the same airports, depending on where they may go. Some of them are central hubs of transportation, and have even become art installations and shopping malls in their own right.
Airports in the United States see the most passenger traffic, with five airports appearing in the top 15. Which other destinations see the most travelers? Click on to find out.