Tiny DC

Matthew Yglesias says that "it's often said that Washington, DC is a surprisingly small city for capital of The World's Only Superpower." But really, it shouldn't be that surprising. After all, it was built for the purpose of being the capital. If it weren't for the US government, nobody would have bothered to drain the swamp on the Potomac. Since there's no independent reason for there to be a city there, it's not inclined to as much growth. The pattern holds for other countries as well -- Brasilia is dwarfed by Sao Paulo and Rio, and Canberra is a fraction the size of Sydney or Melbourne.