In late 2016, American diplomats living in Cuba started hearing a strange noise in their homes. It was high-pitched, deafening, and persistent—and no one could work out where it was coming from.
In the following years, the mystery ballooned into an international incident. Many of the diplomats experienced dizziness, insomnia, hearing loss, and other troubling symptoms. A team from the University of Pennsylvania examined 21 affected people and concluded that they had “sustained injury to widespread brain networks,” based on evidence that other neurologists said was “almost unbelievably flimsy.” Donald Trump, without evidence, accused Cuba of being responsible. Various parties argued that the strange noise was the result of a sonic weapon, a microwave attack, or malfunctioning eavesdropping equipment.