Nicaragua's Contra rebels in 1990. The U.S. backed the Contras in the 1980s, which led to the ouster of the leftist Sandinista leadership. But the U.S. aid violated American law and contributed to the biggest scandal of President Reagan's administration. Michael Stravato/AP hide caption

itoggle caption Michael Stravato/AP

Photos of Luanda, Angola, tell a tale of two cities: sprawling poor neighborhoods and a glitzy waterfront. Saul Loeb/Getty Images; Michael Gottschalk/Getty Images hide caption

itoggle caption Saul Loeb/Getty Images; Michael Gottschalk/Getty Images