Earlier this year, Marc Breman, one of the most prolific crossword creators in Great Britain, released what some papers called the most challenging crossword puzzle in history. Breman creates around 13,500 crossword clues every year for publications like the Daily Mirror, the Daily Express, and the Sunday Telegraph. He has made more than 30,000 puzzles in his nearly three-decade career. But one stands above the rest.

"The World's Hardest Cryptic Crossword" got its title because of its intensely abstruse clues, and it took Breman six weeks to complete. Though the language of each clue—like 44 Down, "Fuss about a large bear," or 51 Across, "Yorkshire flower of zero application"—may read as straightforward, Breman's puzzle is said by the Daily Mail to be challenging due to its "linguistic wordplay, codes and numerous hidden meanings."

So just how hard is it? "Based on the feedback of other compilers who have seen it or tried it, mine is about 100 times harder," Breman told The Mirror in April. "If that description is indeed correct, then it stands to reason that it would take the average enthusiast 100 times longer to solve it. This amounts to 100 weeks, or just over two years."

Breman was so sure of his challenge that he offered a free copy of his 2017 novel, The Foggiest Notion, to anyone who sent him a correct solve.

A victim of its own branding, Breman's puzzle was devoured and solved, by some, relatively quickly. In an interview with The Guardian, Breman said, "[The puzzle] started as a reaction to being asked by a couple of magazines to make things easier. I decided to make the hardest puzzle I could, just for fun." But he did backpedal the claim of its impossible difficulty just a touch: "It's clearly not the hardest puzzle, it's just the hardest puzzle I could make."

Almost immediately, one reader of The Daily Telegraph said he solved the puzzle in under two hours. "I am a very keen puzzler," Simon Anthony told the paper. "Some of the clues were definitely tricky, but two years would be a stretch … it used a lot of interesting vocabulary and cluing, although some of the clues were outrageous." Anthony was the first of 10 people Breman said sent him a correct solution.

Breman's puzzle is available for download here, and it certainly is quite the challenge, even for those who can race through the notoriously difficult New York Times Sunday puzzle. How fast do you think you could solve it? Give it your best shot to celebrate National Crossword Day today! (And if you need some help, check out this video of Anthony solving the puzzle clue by clue.)