Bow and arrow
The bow is the most enduringly effective weapon in human history. Evidence indicates origins as early as 12,000 years ago, and they only became obsolete in the 16th century. The bow and arrow, in its various guises, helped develop many great empires. The Ancient Egyptians used archers heavily, the composite bow was a vital component of great nomad invasions of Europe, including the Huns, Avars, Magyars, and Mongols, while the English longbow was a weapon of fear and proved decisive in many battles. These powerful societies were undoubtedly helped by the potency of the bow and arrow, making this a worthy candidate for the top spot. For related top 10s, check out our Top 10: Unknown Scientists Who Changed The World and our Top 10: Video Game Weapons.