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 Vietnam War was the longest in U.S. history, until the war in Afghanistan that began in 2002 and continues at this writing (2013). It was extremely divisive in the U.S., Europe, Australia and elsewhere.