[Republican soldiers firing machine guns, University City, Madrid]

[Republican soldiers of the International Brigade, University City, Madrid]

[Martin Luther King Jr. addressing Prayer Pilgrimage for Freedom, in front of the Lincoln Memorial, Washington, D.C.]

[Republican soldiers of the International Brigade, University City, Madrid]

[American Abraham Lincoln Brigade, led by Milton Wolff (center), during the final review of the International Brigades, near Falset, Spain]

[American Abraham Lincoln Brigade, led by Milton Wolff (center, without cap), at the farewell ceremony for the International Brigades, near Falset, Spain]

[American Abraham Lincoln Brigade, led by Milton Wolff (center, without cap), at the farewell ceremony for the International Brigades, near Falset, Spain]

[Pearl Primus dancing at a Fiesta Republicana, Dexter Park, Queens, New York]