It's such a peaceful image. A woman handing out fruit to a group of young people. But the print is the product of conflict and pain. The bloody, brutal Mexican Revolution (1910-1920) is the theme of an exhibition of prints at the McNay Art Museum in San Antonio, Texas. At least a million died, fighting for racial and economic equity. And education. "If you were the wrong color, you were not allowed to go to school," says curator Lyle Williams. Some of Mexico's greatest artists, known as Mexican Modernists, joined the protestors. In the image above, Diego Rivera (Frieda Kahlo's husband) draws Mexicans of all races getting apples along with a revolutionary goal: learning. To Williams, the message is "we work hard. The fruits of our labor are education for all." (Click to see Kahlo's 1931 portrait of herself and Rivera.) Rivera, José Clemente Orozco, and David Alfaro Siqueiros, "Los Tres Grandes" (The Three Greats who are the focus of the exhibition) fought tyranny through their...