Tucked away in Belgrade's sprawling Kalemegdan Citadel, this museum presents the complete military history of the former Yugoslavia. Gripping displays include captured Kosovo Liberation Army weapons, bombs and missiles (courtesy of NATO), rare guns and bits of the American stealth fighter that was shot down in 1999. You'll find the museum through the Stambol Gate, built by the Turks in the mid-1700s and used for public executions.