When you think of slaves, what images come to mind? Whether it’s lynchings, cotton fields, or even the ’70s television miniseries Roots, your mental picture is probably of black people. We tend to forget that slavery didn’t begin with the middle passage, or even end with the Emancipation Proclamation. We tend to think nationally, not globally. But according to historian C.R. Gibbs, from the 1600s to the 1800s at least 1 million whites—captured in battles and shipwrecks and sold by European merchants—were slaves in North and West Africa. “As a rule,” says Gibbs, “people are surprised to hear it.” And while this branch of slavery may not have been the institutionalized slavery of the United States, it was still brutal. Gibbs’ Black History Month lecture, “White Slavery in Africa: The Untold Story,” details this little-known footnote to the history of slavery. At 7 p.m. at the Martin Luther King Jr. Memorial Library, 901 G St. NW. Free. (202) 727-1211. (Nefretiti Makenta)