A hundred years ago, London would have made sense as the spot where the world's leaders should gather, as they will this week, to grapple with a spreading economic crisis. The city was the early 20th century's nexus of finance and power, and Britain straddled the globe as the only true superpower. But we're in the 21st century now, and the G20 heads of state should not be plotting in the shadow of Big Ben. They should be sitting across from Mao's Tomb, near the Forbidden City, in the meeting halls off Tiananmen Square in Beijing.