A sprawling 3,500-year-old fortress offers tantalizing clues about a culture that once dotted the southern Caucasus mountains with similar walled communities. Archaeologists recently used a drone to map a sprawling 3,500-year-old fortress in the Caucasus Mountains of southern Georgia. The detailed aerial map offers some tantalizing clues about the ancient culture whose people built hundreds of similar fortresses in a mountainous region that spans the modern countries of Armenia, Azerbaijan, Georgia, and Turkey.