[Contains explicit content] It's called the Dark Web, Dark Net or Deep Web but what is it? What makes this internet underground — rife with drugs, sex, and crime — possible? How do you even access the Dark Web?

Geoff White, Channel 4 News's former Technology Reporter, has been looking into its shady origins and reveals why the U.S. Navy invented it in the first place.

[Contains explicit content] The Dark Web's first success story was a drugs 'eBay.' Vendors sold narcotics and pharmaceuticals directly to each other freely and anonymously. Then the FBI shut it down and unmasked its owner, Ross Ulbricht. The sting operation was ridiculous.

Geoff White, Channel 4 News's former Technology Reporter, speaks with a key player at the heart of the takedown. His story is astonishing.

[Contains explicit content] If money makes the world go around, then Bitcoin keeps The Dark Web spinning. But what it is and how does it work? How can you run a currency based on trust when everyone who uses it is anonymous?

Geoff White, Channel 4 News's former Technology Reporter, uncovers the mystery of Bitcoin - and speaks to the Royal Mint about this potential competitor currency.

[Contains explicit content] When the Munich shootings happened in 2016, Europe feared it was another extremist terror cell at work.

Geoff White, Channel 4 News's former Technology Reporter, found transcripts of the 18-year-old lone gunman from sources on the Dark Web. He tracks down one of the sellers that was in contact with Ali David Sonboly and tries to buy a gun himself.

[Contains explicit content] Hackers aren't solitary loners. They're organised, temporary teams who come together for a purpose — to take down a multinational or expose security weakness.

Geoff White, Channel 4 News's former Technology Reporter speaks to T-Flow, a member of the Lulzsec hacking group, who is now working for the good guys. Why do they do it and how can a team of strangers trust each other?

[Contains explicit content] Every crime story has an elusive big bad boss. So who is the Keyser Soze of the Dark Web?

Geoff White, Channel 4 News's former Technology Reporter, goes on the trail of a computer virus creator who used the Dark Web as perfect cover to unleash a disruptive and lucrative online racket. It became the blueprint for the copycat viruses we still have today.

[Contains explicit content] Dark Web technology has spawned a new kind of extortion and it targets our most trusted institutions — the police, the health service and local governance. Ransomware hold entire computer servers hostage until a ransom is paid.

Channel 4 News's former Technology Reporter, Geoff White, sifts through the records of attacks and tries to make sense of the very corporate franchise model the blackmailers are using.

[Contains explicit content] Most of us assume the online underworld is flooded by images of child sexual abuse. Yet due to the hazards of investigating the Dark Web, it is very difficult to find independent research. So just how much child porn is there on the Dark Web? And what are the police doing to tackle it?

In this episode, Channel 4 News's former Technology Reporter, Geoff White, discovers a shocking truth — that many paedophiles don't need the dark web. They're active in a much more open way.