This flag on South Padre Island, Texas kept me puzzling for some time. I came up with several ideas, none of which were correct. Thanks to the Historical Flags of Our Ancestors website for providing an explanation: “Thin Blue Line Flag…a testament to the valor of police officers across the country. The courage exhibited by officers in the line of duty is represented by the Thin Blue Line in the center of the flag. The solemn black background acts as a memorial to the lives lost while shielding citizens from danger.” I’m glad I asked.