Here is a four-legged robot developed by Defense Advanced Research Projects Agency (DARPA) and Boston Dynamics. The pack bot is designed to offload the increasingly heavy amount of gear soldiers carry onto the battlefield. The robot walks on four legs and has a fast-reacting balance system that means it won't fall over if shoved from one side -- something that most robots can't handle. If it does somehow fall, it's capable of righting itself. There are also "eyes" at the front, actually electronic sensors that constantly scan the surroundings.