Jeans
Mens jeans are pants that are generally made from denim. Jeans became popular in the 1950's among young working men who needed a more rugged, though material that didn't rip during hard manual labor. Over time jeans became common for casual use. Jeans come in many different styles and colors, however blue jeans are by far the most popular style of jeans.
As different groups had differnet needs for jeans, many new popular styles of jeans were born. Boot cut jeans became popular becuase of the United States Navy and it eventually became part of their offical working uniform. The Navy chose jeans because the denim was very strong and prevent rips much better than their traditional uniforms did.