Library of CongressTuskegee Institute President Booker T. Washington works at his desk in a photo taken around 1905.

In his most famous speech, at a cotton exposition in 1895 in Atlanta, Washington implored the agrarian South, which was beginning to industrialize, to put America's 4 million former slaves to work. "Let down your buckets where you are," he said. "You'll find fresh water...a major source of strength for the country."

Washington certainly put his Tuskegee students to work. They dug the clay, built the kilns, fired the bricks, and themselves constructed campus buildings - including Washington's own stately home - that stand to this day.

And Washington hired away another onetime slave, a pioneer botanist and inventor working in the Midwest state of Iowa, who would join him in the pantheon of African-American giants. His name was George Washington Carver.

Peanut miracles

"When he first came into the South, he noticed how the farmers' crops were not producing a lot and that all the nutrients were sucked out of the soil," notes Shirley Baxter, a U.S. National Park Service ranger at the George Washington Carver National Historic site on the Tuskegee campus.

"He knew that if they planted legumes, if they rotated their crops, that that was really going to help them as a people. And when they started growing peanuts, they asked him 'What do we do with them?' And that's when he went into the lab."