It's perhaps no surprise that the United States has more unmanned aerial devices than any other country. With its veritable army of drones, America has killed more than 2,000 people over the years -- most recently, senior al-Qaeda figure Anwar al-Awlaki.
However, the U.S. isn't alone: More than 50 countries have built or bought UAVs -- and more are investing in the technology every month.
The roster of UAV-weilding nations now includes Israel, Britain, China, Armenia, Latvia and Vietnam. Why all the interest in unmanned vehicles? They pack more of a punch than their alternatives; meaning, more people can be killed (or simply found) using fewer resources and less money. For example, high-performance drones like the popular Predator cost between $10.5 million and $20 million each, far cheaper than an F-22 fighter jet at $150 million.
China has also been rapidly growing its UAV research capabilities over the last five years. Its crowning achievement, the WJ-600 unmanned bomber, is a force to be reckoned with. Meanwhile, Russia, India, Iran and Pakistan are launching their own UAV development efforts: all in the name of hands-off war.