Mongolia, a vast, sparsely populated country almost as large as Western Europe, is at once strikingly poor and strikingly rich. Its GDP per capita falls just below that of war-torn Iraq, and Ulan Bator has some of the worst air pollution ever recorded in a capital city. At the same time, Mongolia sits atop some of the world’s largest mineral reserves, worth trillions of dollars, and its economy, already one of the world’s fastest growing, could expand by a factor of six by the end of the decade as those reserves are developed.