The Deep Web. What is that i hear you say.
The deep we is a very interesting place. There is everything from information/hacking forums to Black Market online stores. You do need to be careful an not click on anything you are unsure of...BE WARNED!!
To access the deep net you will need most importantly common sense. There is a lot of dodgy shit on there. Then you will need to download The Onion Router (TOR). Just google Tor Project.
Once you have this there is more security you can use which to be honest i would google as it can be tricky if you do not know what your doing but you can now start browsing the Deep Net.
To navigate the deep web the easiest way is to search for deep web crawlers such as Harry 71. These sites are only accessible via Tor but links can be found on reddit and deepdotweb etc.
My advice to you if you are new to browsing. Watch some you tube first on deep web exploration but do not get put off by what you hear. Yeah there is some crazy fucked up shit and some stuff would probably mentally scare you for life but on the other hand there is stuff you will just piss yourself laughing at.