The most important unsolved problem in mathematics — and you can understand it.
The curve above is the Riemann zeta function, tracing its path through the complex plane. Every time it threads the marked origin, it reveals a secret about the prime numbers. The Riemann Hypothesis — unproven since 1859, with a million-dollar prize on its head — says those crossings follow a single, perfect rule.
This site takes you there in five levels, starting from nothing but multiplication.
The ladder
Five levels, each self-contained. Beginners start at the top with Level 1; if you already know some of the story, jump in wherever you like. Every level also hides deeper material behind ★ Go deeper panels — a curious fifteen-year-old and a professional mathematician should both leave satisfied.
- 1The Atoms of ArithmeticWhat primes are, and the strange way they hide.Needs: Nothing beyond multiplication.
- 2Counting the UncountableThe prime staircase, and the curve that shadows it.Needs: Comfort reading a graph. Logarithms introduced gently in-page.
- 3The Golden KeyAn infinite sum that secretly knows every prime.Needs: Willingness to meet infinite sums and complex numbers — both introduced in-page.
- 4The Critical LineThe hypothesis itself — and the music it conducts.Needs: Level 3.
- 5Where We Stand165 years of attack: what we know, what we believe.Needs: Level 4 for full value, but skimmable by anyone.
◆ difficulty — from “no math needed” to “bring complex numbers”
What is this site?
A museum exhibit crossed with an interactive textbook. Each level pairs a handful of ideas with visualizations you can poke at — sieves you step through, races you referee, infinite sums you assemble by hand. Text supports the pictures, not the other way around.
Two promises. Honesty: nothing here is dumbed down into falsehood; when a step needs machinery beyond the page, we say so and show you the shape of it. Wonder: the Riemann Hypothesis sits at the bottom of a real mystery — why the primes, the most jagged objects in mathematics, obey a law of almost supernatural precision. By Level 4 you will see that law drawn on screen, built from the actual zeros of the actual zeta function.
No account, no installs. Your progress lives in your browser. Start anywhere; the ladder in the sidebar always shows where you stand.
Made by Adil Moujahid — more projects and writing at adilmoujahid.com.