In terms of physical size, the biggest/largest airports in the world are:
The Dubai World Central International Airport is currently under construction and due to be fully operational by 2017. It will have 6 x 4.5km long runways, underground parking for 100,000 cars, capacity for 4 planes to land at the same time, 16 cargo terminals capable of handling 12 million tonnes per year and the airport will be able to handle over 120 million passengers per year - which is 30% more than Atlanta - the busiest airport in the world.
It may seem like a question with a simple answer, but many of the worlds big airports claim to be the busiest under different criteria. Basing "busiest" as the most number of passengers, the top 5 busiest airports in the world are:
Anything we didn't cover in this article? Been to one of the airports mentioned? Other airports which you think are amazing? Let us know in the comments below!