The darknet offers a smorgasbord of illegal activity from drugs and arms to child pornography. But political activists and whistle-blowers also find refuge in the darknet's anonymity.
Mainstream search engines cover only about 20 percent of the internet. Most users steer clear of the darknet and Deep Web. But this vast parallel online universe is far more than a den of iniquity and shady dealings. It has its bright spots as well. For example, highly sensitive documents were funneled to WikiLeaks through the darknet, and Edward Snowden is said to have used it to contact reporters.