STUTTGART, Germany (AP) — Marine Gen. Michael Langley took over as the top U.S. commander for Africa on Tuesday, heading U.S. military operations on a continent with some of the most active and dangerous insurgent groups and a relatively small Pentagon footprint. Langley, who made history on Saturday when he became the first African American in the Marine Corps to be promoted to four-star general, took over U.S. Africa Command in a ceremony at Kelley Barracks in Stuttgart, Germany. He is the second African American to lead the command, which has about 6,000-7,000 troops across the continent.