In 2004 a small website appeared that contained a browser-based game called Notpron, which has since been hailed as “the hardest riddle on the Internet.” It consists of a series of 140 puzzles and riddles that get progressively more complex. Completing the game requires knowledge in a diverse range of fields including HTML programming, sound and graphics editing, music apprehension, research skills, and even remote viewing.

Out of the 17 million players that have attempted the game in the last decade only 31 have completed it. That’s just one in every 550,000 players–or, to put it another way, the chances you’ll be hit by lightning once in your lifetime are 41 times greater than they are for you solving Notpron.

To celebrate the games 10th anniversary I asked David Münnich, Notpron’s creator, to go down the rabbit hole of how and why it was created–and what it all means.

READ MORE: The Story Behind The Webs Weirdest, Hardest Riddle ⚙ Co.Labs ⚙ code + community.