Cicada 3301 Explained: The Internet's Hardest Puzzle

Nova, our AI presenter, tells this one in about 40 seconds. Here is the written version, with where each fact comes from.

The short version

In January 2012 an image appeared on 4chan, signed "3301". Its text said the senders were looking for "highly intelligent individuals" and that a message was hidden in the picture. That was the start of Cicada 3301, a series of online puzzles. The name comes from a cicada image that kept turning up inside it.

The first round ran for about a month and was completed: its close read "We have found the individuals we sought." Two more rounds followed, in 2013 and 2014. The third led to the Liber Primus, a book written in runes, and most of it is still undeciphered.

How the first round worked

The puzzle was a chain. Inside the image was hidden text, then a book code, then a phone number, then prime numbers and a website with a countdown. Reports also describe physical posters carrying a cicada and a QR code in places around the world, from Warsaw to Hawaii. Cryptography, number theory and real-world legwork all came into it, which is why solvers formed groups.

What happened to the solvers

One 2012 solver told Rolling Stone that a small group who finished were let into a private site and asked about privacy and information freedom, and that they were later dropped when the site vanished. That is one solver's account, so treat it as that. The 2014 round's third puzzle is reported as unsolved.

Who built it? Nobody knows

The group never said who it was. The three common theories are theories, not facts:

• Team Recruiter: it was a recruiting test, and the privacy questions fit that.
• Team Game: it was an art project or a game, and nobody has ever claimed it.
• Privacy society: a group that wanted to promote cryptography and anonymity. Solvers have said as much, which again is their account.

Facts settle what the puzzle was and how far it got. They don't settle who made it. Which would you bet on?

Transcript

Nova: Cicada was solved. In a month.

A four-chan image seeks "highly intelligent individuals."

Inside: a book code. A phone number.

QR posters, around the world.

Code, maths, Warsaw: so solvers teamed up.

Strangers teamed up. Some got in.

Then they were dropped. The third puzzle? Still unsolved.

A book of runes. Most pages, unread.

Team Recruiter! It asked about privacy. Team Game! Nobody claimed it. Which do you buy?

Sources

• NPR (2014), The Internet's Cicada: A Mystery Without An Answer
• Boing Boing (2026), An anonymous group posted internet puzzles to recruit code-breakers, then vanished
• CBS News, Is this a clue for online code-breaking scavenger hunt Cicada 3301?
• Slashgear, The Strange History Surrounding Cicada 3301
• Grunge, The Weird True Story Of Cicada 3301
• Rolling Stone (2015), Cicada: Solving the Web's Deepest Mystery
• WNYC Note to Self (2013), Meet the Teenage Codebreaker Who Helped Solve the Cicada 3301 Internet Puzzle
• Interesting Engineering, A modern day treasure hunt: cracking Cicada 3301

Nova is an AI-generated presenter and her voice is AI-generated; the visuals are our own graphics. We do not show the original puzzle images. Not affiliated with the creators of Cicada 3301.

This video is made with AI tools and reviewed by people before release. See how we make our videos.