On May 24, 1869, the Powell - Colorado River Expedition, ten men and four boats strong, set out from these environs on a voyage whose result was civilization's first definite knowledge of this continent's last unexplored major river drainage. Ninety-eight days later, six battered river veterans emerged from the once-shaded but no longer unknown depths of the Grand Canyon to beach two water-worn and rock-mauled boats in triumph. The expedition's suspense, danger, and action won the admiration of a nation, and John Wesley Powell, credited with rare executive and scientific talents, rose from that acclaim into public service and the highest councils of the republic. In later years, his sharpened executive ability helped create and make productive important federal agencies, while his scientific genius advanced ethnology, geology, and agronomy. A gift of lasting national consequence, conceived during the Colorado River explorations, was his theory of arid-land culture, developed through his success in fathering the Bureau of Reclamation, which changed western landscapes and caused extensive regions to blossom and thrive.