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.
How many years did world war 2 last for? 6 years, from September 1st, 1939 with the German invasion of Poland up until VE Day (Victory in Europe) on May 8th, 1945 and/or VJ Day (Victory in Japan) on August 14th 1945.