SAN DIEGO — The dark web. It sounds like a mysterious place, but what is it, really?

Think about the web as the ocean; at the surface, where there's sunlight and everything's visible is where we spend most of our time. It's where we do our google searches, shop on Amazon, and access most of our information.

Go down a little deeper in the ocean and it's a bit murky, with filtered light - this is what's known as the deep web; government databases live here, your company employment data, restricted access sites, not generally available to the public like the ones at the surface.

Then, travel farther down to the depths of the ocean and this is where you'll find the dark web; where no one can see what you're doing, everything is anonymous, and this is where criminal activity flourishes.

It's the hidden part of the World Wide Web most people have never seen.

FBI Special Agent Chris Christopherson took News 8’s Marcella Lee inside this underground world, giving her a first-hand look at the nefarious transactions that take place there.

When asked about the most common criminal activities on the dark web, Christopherson brought up drugs.

"So, the sale of drugs represents about 50 percent of illicit commerce on the dark web,” he said. “There's all sorts of drugs for sale, and they even indicate the type of heroin that it is.”

On the dark web crimes are committed with the simple click of a mouse..

"Click the type of drug that you want and as we scroll down you can see what it looks like,” said Christopherson.

Heroin, cocaine, and ecstasy are all readily available, but does it come to your door like a package from Amazon?

“It does in fact,” said Christopherson.

You can also buy illegal services.

“On the dark web you can rent a hacker,” said Christopherson. “As you see here, you potentially could rent a hacker to help you get on someone's Facebook page or get into their email account and you can see the price here, you're looking at about 250 Euros.”

That's about $285.

One hacker Christopherson showed News 8 is even willing to plant child pornography on the computer of someone you know.

It’s an international black market.

“Here we have a site where we can purchase credit cards and they sell them in bulks of 100,” said Christopherson.

The numbers on those cards could belong to anyone. Identity theft runs rampant.

“Someone who works for a collections company has a stash of data and is willing to transact it to other people on the dark web,” Christopherson said.

Your digital data: logins, passwords, mother’s maiden name - sold and used by crooks.

So, how do you access the dark web?

"You just install a browser, and you're on it” Christopherson said.

It's that easy - you can download the TOR browser for free.

"TOR stands for The Onion Router,” said Christopherson.

The onion is symbolic of multiple layers of privacy.

“We’re routed through three different servers in France,” Christopherson said. “Each layer is a layer of encryption.”

Each layer providing anonymity.

"The dark web, it promises anonymity for a website, for people to access the website, and for transactions to be conducted anonymously,” he said.

But where did the dark web come from?

“The dark web was born out of the U.S. Navy,” said Christopherson. “So as a U.S. government project, they started TOR and TOR gives us the dark web.”

The technology was developed in the 1990s to protect U.S. intelligence communications online and has has some legitimate uses today, including for people in countries subject to censorship.

“There are computer science majors, there are people who are interested in it, who just want to see how it works,” said Christopherson. “So, just because someone is on the dark web or TOR is not in and of itself an indication fact that they’re bad.”

Still, Christopherson, who investigates cybercrimes out of the San Diego field office says parents should be familiar with the .onion domain.

"If you see these types of addresses in text messages, it might be a good chance for a parent to start a conversation or dig deeper into it,” he said.

He also has this warning to those who buy and sell on the dark web:

"The one thing that benefits law enforcement and the greater good is if you did purchase this, you don't know if you're purchasing the service from me, and you don't know if you're purchasing it from someone who won't just take your money,” said Christopherson. “It's hard to really determine if this is in fact what you'll get, or if you're purchasing this from someone in law enforcement.”

Christopherson also wants people to know what goes on there and says you can protect yourself from identity left in these ways:

1. Monitor your credit

2. Protect your information

4. Protect your passwords

5. Be mindful on social media

6. Be wary of open wireless networks

7. Be smart with your smart phones