At the time, the Soviet Union and the United States were in an arms race of a bizarre, unconventional kind - that has been exposed in a new report.

Beginning in 1917 and continuing until 2003, the Soviets poured up to $1 billion into developing mind-controlling weaponry to compete with similar programs undertaken in the US.

While much still remains classified, we can now confirm the Soviets used methods to manipulate test subjects' brains.