Los Llanos-the rain-leached, eastern savannas of war-ravaged Colombia-are among the most brutal environments on Earth and an unlikely setting for one of the most hopeful environmental stories ever told. Here, in the late 1960s, a young Colombian development worker named Paolo Lugari wondered if the nearly uninhabited, infertile llanos could be made livable for his country's growing population. He had no idea that nearly four decades later, his experiment would be one of the world's most celebrat