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.
A war can last days to years. A battle can last hours to days. As an example. The conflict between the United States of America and the Confederate States of America over the independance of the Southern States from the United States is called the Civil War. It lasted 4 years, 1861-1865.