Because there’s poverty, and war, hunger, and AIDS, and because when adolescent girls in the developing world have a chance, they can be the most powerful force of change for themselves, their families, communities, countries, and the planet. But while those 600 million adolescent girls are the most likely agents of change, they are often invisible to their societies and the world. So what can we do about that? Invest in girls. Make them visible. Break the cycle. Change the world.