When you hear the words “big city”, what pops into your head? For most Americans, New York is the quintessential big city. For most Brits, it’s London. For those living in rural Appalachia, it might be Charleston, West Virginia, a town of about 50,000. But none of these cities are even in the top 20 most populous worldwide. Everyone knows about Beijing and Tokyo, but we bet at least a few of these places you haven’t heard of, let alone realized they were bigger than the Big Apple. And there’s a fair chance there will be a couple you can’t even pronounce.