A few things I found out about cargo pants:

• Cargo pants hail from World War II, when the military used only olive drab, or "OD green" fabric. Now official cargo pants are available in camouflage colors.
  
  
• Cargo pockets were designed for utility. The deep pockets on the legs could tote plenty, and they were easily accessible.
  
  
• Official Army cargoes are six-pocket pants with a double seat, double knee, pull-tab waist and drawstring bottom.
  
  
• Zippered pants were a staple during WWII. Now buttons are the norm, because in battle it's easier to replace a button than a zipper.
  
  
• Computers have made their mark on military garb in the form of digital camouflage.