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04 April 2023
10 minutes
Eternity II Puzzle - The Hardest Puzzle in the World

Eternity II Puzzle - The Hardest Puzzle in the World

The realm of puzzles has always been an enticing world for those who seek mental challenges and stimulation. However, one puzzle has continually defied logic and stumped even the most skilled enthusiasts: the Eternity II Puzzle. Let's delve into the origins, design, and reasons behind the Eternity II Puzzle's infamy as the hardest puzzle in the world. And we will also discuss various attempts to solve it and the ongoing fascination it holds for puzzle enthusiasts.

The Mind Behind Eternity II

British puzzle creator and mathematician Christopher Monckton is the mastermind behind the Eternity II Puzzle. With a penchant for creating intricate and challenging puzzles, Monckton has gained a reputation for developing brain teasers that push the limits of human problem-solving capabilities.

Inspiration from the Original Eternity

The Eternity II Puzzle is a sequel to the original Eternity puzzle, which was also designed by Monckton. Released in 1999, the original Eternity puzzle consisted of 209 irregularly shaped pieces that had to be arranged within a 12-sided grid. The first Eternity puzzle was so difficult that it took two mathematicians, Alex Selby and Oliver Riordan, nearly two years to find the solution. Monckton had offered a prize of £1 million to the first person who could solve it, and in 2000, Selby and Riordan claimed the prize.

The Birth of Eternity II

Motivated by the success of the original Eternity puzzle, Monckton set out to design a sequel that would surpass its predecessor in terms of complexity and difficulty. After years of research, experimentation, and design, Monckton released the Eternity II Puzzle in 2007. This new puzzle was designed with 256 square pieces, each with a unique pattern, which significantly increased the challenge compared to the original Eternity puzzle.

The Puzzle's Design

The Eternity II Puzzle consists of 256 square pieces, each with a unique pattern. The objective is to place these pieces within a 16x16 grid, matching the colored edges of each piece with its neighbors to create a perfectly aligned grid. Unlike many other puzzles, Eternity II's pieces have no rotational symmetry, dramatically increasing its difficulty.

The Challenge

The Eternity II Puzzle is notorious for its daunting level of complexity. With 256 pieces and no rotational symmetry, the number of potential solutions is astronomical, making it nearly impossible to solve through trial and error. Even the most dedicated and skilled puzzle solvers find themselves at a loss when faced with this behemoth of a challenge.

The Prize

To sweeten the pot, the Eternity II Puzzle offers a staggering $2 million prize for the first person to solve it. This unclaimed prize has been on offer for over a decade, further solidifying the Eternity II Puzzle's reputation as the hardest puzzle in the world.

Attempts at Solving

Over the years, various methods have been employed in an attempt to solve the Eternity II Puzzle. These methods include:

  1. Brute force: Trying every possible combination of pieces in the hope of eventually finding the correct solution. However, due to the vast number of potential combinations, this method has proven inefficient and unfruitful.
  2. Heuristics: Using problem-solving techniques and strategies to simplify the puzzle, making it easier to solve. Despite the application of various heuristics, no solution has been found.
  3. Genetic algorithms: Using computational methods that mimic the process of natural selection, genetic algorithms have been employed to search for a solution. Although these algorithms have shown promise in solving other complex problems, they have yet to crack the Eternity II Puzzle.

The Ongoing Fascination

The Eternity II Puzzle has captivated the minds of puzzle enthusiasts worldwide. Its intricate design, elusive solution, and tantalizing $2 million prize have made it a constant source of fascination and intrigue. As more individuals and groups take up the challenge to solve it, the Eternity II Puzzle remains a testament to human ingenuity and our passion for solving complex problems.


The Eternity II Puzzle stands as a true enigma in the world of puzzles. Its unique design, immense difficulty, and the unclaimed $2 million prize make it a fascinating subject for both puzzle enthusiasts and casual observers alike. As the search for the elusive solution continues, the Eternity II Puzzle maintains its undisputed title as the hardest puzzle in the world.