They want bigger warships, bigger tanks, and bigger explosions. Sometimes however, the littlest things can be the most dangerous. In fact, developments in nanotechnology may be about to usher in a new class of miniaturized weapons that shouldn't be underestimated.

CNBC recently interviewed physicist and futurist Louis Del Monte on his new book "Nanoweapons: A Growing Threat to Humanity." The future it paints sounds absolutely terrifying:

One unsettling prediction Del Monte's made is that terrorists could get their hands on nanoweapons as early as the late 2020s through black market sources.

According to Del Monte, nanoweapons are much smaller than a strand of human hair and the insect-like nanobots could be programmed to perform various tasks, including injecting toxins into people or contaminating the water supply of a major city.