For some, it began with a sharp sound followed by a wave of pain and nausea. Others describe hearing crickets on a soft summer evening, then being overcome with dizziness, an inability to remain balanced. A few even speak of feeling some kind of force, a shock wave of pressure that left them with blinding headaches and bleeding noses. Regardless of how it began, the results for 39 Canadian and U.S. Diplomats were the same—years of living with a debilitating illness. To this day, neither the best scientific minds in the world, nor the most astute spies and diplomats can provide a definitive answer to the unsettling question: What happened in Havana?