The Airports Council International, which governs roughly 1,650 airports worldwide, released a preliminary list of the world's busiest airports (numbers 1 through 30) on Tuesday, and there were some surprises. Beijing came in #2 behind Atlanta-Hartsfield Airport; Chicago's O'Hare airport overtook London's Heathrow for the third spot. The ACI reports that world passenger travel rose 6.3% to roughly 4.7 billion passengers in 2010, despite a volcanic ash cloud which virtually shut down air travel in Europe for weeks last spring and an incredible number of winter storms which halted travel around the globe.Heathrow and Las Vegas's McCarren were the only two of the world's biggest airports that saw a decrease in traffic in 2010.