According to Forbes, the rifle ranks as the 7th "most important tool of all time, in terms of its impact on human civilization."

For as long as humans have created tools, they've made projectile weapons. Our ancestors made spears, slings and bows and mastered their use in hunting and warfare. But the rifle put all those tools to shame, boasting unprecedented accuracy, power, reliability, and range. Rifles have won wars, tamed continents and overturned empires.

What's more the rifle required much less training and skill than it's predecessors. Mastering the sword, which ranked 8th, could take a lifetime. But learning how to shoot is easy and requires much less physical acumen. It also defeated armor and bigger guns (like heavy cannon) made the castle and other structural fortifications obsolete.