Why can’t we access the sites in the Deep Web (Onion/Tor) without a specially built browser?

Answer by Franck Dernoncourt:

We can. E.g. for Chrome follow the instructions: How do you configure Google Chrome to use TOR?

1. Download Vidalia from
Download Tor
2. Install Vidalia – a TOR client with GUI.
3. Wait until Vidalia tells you that Tor is working.
4. Start Google Chrome.
5. Using the Tools menus (it looks like a wrench), choose options, “Under the hood”. Scroll down to “Network” and click the “Change Proxy Setting” button.
6. Under the “Connections” tab, choose “LAN Setting” – Select Use Proxy server and enter “Localhost” and port 8118.
7. Save your work and return to the Chrome web browser. Check that you are using TOR by going to
Are you using Tor?
A Green message will indicate that TOR is operating correctly. A Red message will indicate that TOR is not set up correctly.
8. Continue to surf using TOR

On Firefox there used to be a nice extension for this, but it has been stopped due to Firefox:
Tor Project: Torbutton :

Torbutton is the component in Tor Browser Bundle that takes care of application-level security and privacy concerns in Firefox. To keep you safe, Torbutton disables many types of active content.

Now that the Tor Browser Bundle includes a patched version of Firefox, and because we don’t have enough developer resources to keep up with the accelerated Firefox release schedule, the toggle model of Torbutton is no longer supported.

Regarding Freenet, you can also choose any browser you want.

Lastly, you confuse Deep Web with Tor/Onion. Check out Deep Web.

Why can’t we access the sites in the Deep Web (Onion/Tor) without a specially built browser?

 

I also found following from REDDIT thread here:

Background – The so called “Deep Web” is the name of the part of the internet that is not indexed by search engines. It is made to be browsed anonymously and therefore you can only access it by a specific method (see below). It uses mainly .onion URL extension and random combinations of letters and numbers for the domain name.

Content – The deep web contains almost everything, if you have the time to look for it. Content on the deep web can be generated per query, and therefore the amount of content it actually has might be greater than you might expect. However, when you combine a completely anonymous way of access and the internet, you obviously end up with a lot of child porn, illegal drug trade, hiring of trained killers, etc. But, if you ignore that stuff, you can find a lot of interesting topics here, and it is also a good way to get a status update on the armpit of society. The main access route to the deep web is known as “The Hidden Wiki.” It contains most of the .onion links that you will need to go skinny dipping in the shark tank known as the internet.

Access – Accessing the deep web is entirely up to you. I went on for the first time today, and so far have not had my identity stolen, and no police have shown up at my door. Maybe I am just lucky, maybe this is how it always is. I do, however, HIGHLY recommend you check this place out. It is very interesting, and you get to venture in to a brave new world full of things that will both shock and intrigue you.

With that said, here is all you need to access the deep web:

Tor Browser: https://www.torproject.org/download/download.html.en (download the Tor Browser Bundle)

The Hidden Wiki: http://kpvz7ki2v5agwt35.onion/wiki/index.php/Main_Page (once you have Tor up and running, enter this link in to the browser and prepare yourself)

Enjoy yourself, and remember: STAY SAFE! I cannot stress that enough. I do not know how dangerous this place is, but I do know that bad people lurk around there. Just try not to get too involved with whatever “community” you may find, and you should be fine.

EDIT 1: For information, visit the Wikipedia article.

EDIT 2: This is a picture of “The Hidden Wiki”

EDIT 3: The Hidden Wiki is currently DOWN.

 

This article is combined from a quora answer and reddit post. See them here and here.