It’s a part of the Internet that can’t be accessed via traditional means and browsers, Dark Web sites don’t show up in Google searches
The only browser you can use on the Dark Web is something called TOR which stands for The Onion Router and packets are broken up, encrypted and routed through the internet using different paths the reach the destination making traffic untraceable
It allows anonymity on the internet and is untraceable
When you combine the Dark Web with crypto currency like Bitcoin you have the ability to conduct business, while remaining anonymous and untraceable
It was the reason that allowed Ross Ulbrecht to run The Silk Road site for so long and flaunt it to Government, he was eventually caught because of something he did outside of the Dark Web
He was arrested while doing admin work on the Silk Road site while sitting in a Public Library in San Francisco