A suspected spy balloon from China was spotted over Montana and floated above the U.S. until the military shot it down in South Carolina with a missile, per the Deseret News. Spy balloons entered the cultural consciousness due to the recent spotting, but they have been around for decades.

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One of the earliest instances of balloons as spying devices occurred in 1794, when Napoleon Bonaparte’s soldiers used them for espionage. CNN detailed how Union forces during the Civil War also used balloons to spy on enemy forces.

While the Confederate side also used balloons, the Union’s use of balloons was superior. The New York Times reported, “The Union had better balloon resources than the Confederates, including a boat to which a balloon was tethered, in what amounted to an early version of an aircraft carrier.”

These balloons have been used throughout other wars as well. During World War I and World War II, balloons were used for both spying and bombing, according to The Atlantic. One American pilot known as Frank Luke shot down 14 different spy balloons from German forces over the course of a few weeks in 1918.

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From 1944 to 1945, Japanese forces deployed around 9,000 spy balloons into the U.S., some of which were found in various states, according to The New York Times. The U.S. has also used balloons for observational purposes, as well as in Europe and in Afghanistan.