"By 2050, almost 70 percent of the world's estimated 10 billion inhabitants—or more than the number of people living today—will be part of massive urban networks. ... These staggering statistical trends are driving the evolution of the 'megacity,' defined as an urban agglomeration of more than 10 million people. Sixty years ago there were only two: New York/Newark and Tokyo. Today there are 22 such megacities—the majority in the developing countries of Asia, Africa, and Latin America—and by 2025 there will probably be 30 or more."