These are the 19 most game-changing weapons of the 21st century

The imperatives of the military have always been one of the main drivers of technological development.

ARPANET, one of the internet's most important precursors, was a Pentagon project while most of the technology in an iPhone originated with the US Department of Defense.

Just as smart gadgets have invaded our homes and revolutionized our lives over the last 15 years, next-level weaponry has transformed the military.

Today, militaries and irregular forces around the world are still pushing technological boundaries.

Everything from concealed roadside bombs - cheap, primitive, and deadly - to multibillion-dollar aerial lasers have transformed conventional methods of combat and altered the world's technological and political landscape.

Here are 19 of the most important weapons of the last 15 years.