On the morning of August 28, 1963, National Geographic photographer James P. Blair left his apartment on the corner of 17th and M Streets in Washington, D.C.

Blair lived only a block from the National Geographic Society, where he’d worked as a staff photographer for a little over a year. But on that day—a Wednesday—he didn’t go into the office. Instead, he walked to the Washington Monument to photograph the March on Washington for Jobs and Freedom.

Organized by leaders of the civil rights movement, including Martin Luther King, Jr., and John Lewis, the march was a culmination of years of frustration over segregation and inequality. More than a quarter of a million people attended, and thousands of