The Ozone layer, which mostly lies on the lower portion of the stratosphere.
How Long Did The Vietnam War Last. The Vietnam War is the longest war ever to have taken place in the American history. It lasted for 16 years and it was terrible for the Americans at that time as the Civil Rights campaign was at its peak and so also the Vietnam War and anti war protests.
The longest American war was the Vietnam War which lasted for 25 years (1945-1975). America entered the war in 1959. that's not even close to the right answer. There are alot of different angles but the US did not enter the war until 1965.