Kibera, Kenya (CNN) -- Heaps of trash pile up for miles in Kibera, a district of Nairobi that houses nearly 1 million people and is one of the poorest slums in the world. Aluminum shanties fill the horizon, and an odor of urine cuts through the air. A man trots through the narrow, unpaved streets on a camel. If you make your way through this crowded maze, however, you will find the Kibera Girls Soccer Academy, a free public school for girls and, recently, a few boys. Peek in through the windows, and you'll see a sight that seems incongruous next to the grimy chaos outside.