Spy Gadgets

In the jungles of Vietnam, the U.S. military built sensors that could sniff out hidden enemies; a CIA operation hauled a nuclear-powered surveillance device to the summit of a Himalayan mountain; and at the height of the Cold War, the Soviet Union slipped a covert listening device inside a seemingly innocent gift presented by schoolchildren to the United States; sometimes the most dangerous weapon in the room is the one nobody realizes is there.