When Francis Kéré set out to build a school in his home village of Gando, Burkina Faso, he chose clay, a material his own community associated with scarcity, not architecture. To prove it could hold, he built test bricks and submerged one in water for five days before showing his neighbors it hadn't failed. Then he trained the villagers themselves to raise the walls, rather than bringing in a construction crew from the city. More than 200 people from Gando have since worked as builders because