On October 22, 1957, American forces suffered their first casualties in Vietnam when 13 Advisory Americans were wounded in three terrorist bombings. Here are 5 things you probably didn't know about the Vietnam War...

American Troops Used People Sniffers One of the weirder tools used by the Americans during the Vietnam War was the "people sniffer", also know as Operation Snoopy. Northern troops on the Ho Chi Minh Trail were notoriously difficult to find, so the Americans used sensors to detect human sweat and urine. These sensors were deployed when troops wanted to find anyone who might be hiding. While they frequently turned up false results, leading to attacks on civilians and cattle, they did prove to be somewhat effective. The North Vietnamese Army eventually learned to hang buckets of mud mixed with urine from trees to throw off the sensors.

Americans Played Ghost Noises In The Jungle One of the ways American troops would try to weaken North Vietnamese troops was to scare them into thinking they were surrounded by ghosts. American troops would play recordings that sounded like ghosts were haunting the area. This was called Operation Wandering Soul and was based on the Vietnamese belief that dead people needed to have a proper burial ritual or they would become wandering ghosts. Since many bodies didn’t get proper burials during the war, there would’ve been plenty of upset ghosts. The Americans preyed on this fear by playing ghost noises on hidden speakers in the jungles at night.

It Wasn't Technically A "War" It looked like a war and affected people like a war would, so the battles that took place in Vietnam are referred to and treated as a war. At least, unofficially speaking. In official terms, the years of fighting and death are technically a conflict and not a war because the U.S. never officially declared war on Vietnam or any of the forces fighting there. This meant the war was technically a conflict, though neither side actually thought of it this way.

The Death Toll Was Almost Entirely Vietnamese In the Vietnam War, 58,220 Americans died. By comparison, including both north and south, approximately 2 million Vietnamese civilians died. That doesn’t even include soldiers, which would add another approximately 1.35 million Vietnamese deaths. That puts Americans at less than 2% of the total deaths.

It’s Called The American War in Vietnam Wars generally have names that distinguish them from other conflicts in the same country. The Americans refer to the war in Vietnam as the Vietnam War. For the Vietnamese, however, the war is called the American War (or, in full, the “War Against the Americans to Save the Nation”).