What's the world's hardest puzzle?

Before looking at what The Isis Adventure is, let's take a look at what it's not. It's impossible to complete the entire adventure without the puzzles that go along with it. Unlike a classic math problem or word and logic mind game, each level of The Isis Adventure Series has an object to crack into. While there are options for subscribing to a membership and playing the game online without buying the puzzles, the ultimate winners and prizes come through both the puzzle "pieces" and the continuing online game after players crack the puzzles to reach the keys inside.

Another distinction is that the puzzles in the series are pricey by puzzle standards; the game isn't in the price range of the typical board game or puzzle ball, for example. Ranging from $145 to $5,600 for special edition pieces, the puzzles are handcrafted objects made from metals and alloys and boxed and sealed. If the seal is broken and the box is opened, the puzzle is non-returnable. Some players see this as a criticism but others appreciate that the objects are a true joy to hold and unravel and that once the puzzle itself is handled, the steps in solving it might be compromised.

There are a total of five puzzles in the adventure:

Once they remove the puzzles from their packaging, each puzzle owner needs to register at the Sonic Games Limited/Isis Adventure Web site. Those who solve the Isis are "keepers" who move on to part two, the Ramisis. One word of caution from the Web site, though: "If you damage the Isis, the secret will be lost forever" [source: Sonic Games].

Playing the game starts with cracking the combination of the Isis puzzle, and with a band of ancient Egyptian hieroglyphics and cryptic clues, gamers have spent anywhere from a day to months before getting to the center of the alloy orb. Once inside, have they solved the puzzle?

See what mysteries await after the first ball is opened, next.

In addition to buying and solving each of the five puzzle objects, players need to then enter the code inside the puzzle on the Sonic Games Web site to continue the challenge and become eligible for prizes. What happens next is pretty mysterious until you open the puzzle and register, but continuing the game involves treasure hunts, hidden pyramids and keys -- both real and virtual -- and location-specific searches for cash and gold and silver coins valued at up to $750 or more in 2011. Of the 16,000 or so players from 18 different countries, there have been just 137 winners and 17 treasure hunts. Sonic Games promises that the players who are actually able to unlock the different Isis puzzles will find "an unbelievable and fascinating global pyramid treasure hunt that will take them to places they've never dreamed of going" [source: Sonic Games].

If you like to look at the last few pages of a book early into reading it or to cheat just a little when stumped on a riddle, you can do the same with the world's hardest puzzle. While the hints and tips won't come from the makers of the game, online videos, forums and helps pop up everywhere and with surprisingly respectful warnings that there are spoilers or giveaways that could help someone solve the puzzle and end the challenge.

When Rubik's Cubes were all the rage, it wasn't hard to find someone who had it figured out and could get the colored sides all lined up in seconds. Many of the solvers had numbered guides showing players how to turn the levels of the cube to fix an out-of-position colored square. Some players chose to take just a couple of clues and others memorized all the variations and enjoyed the game for the speed they had in "solving" it with the answers provided.

Anyone who plays the Isis Adventure can get hints and answers, though each puzzle is said to be entirely unique, with its own set of codes. But even if an owner of one of the puzzles gets the needed help and solves the puzzle, it is a different experience than the Rubik's Cube because once an Isis puzzle is opened, it can't be put back together and solved again and again. Some players lament the fact that they can't rebuild the puzzles and display them after solving because they are such well-crafted pieces.

People have been playing the Isis Adventure since 2006, and with the last piece expected in 2015 it will have had at least a good decade of avid playing around the globe. It is unique among puzzles for its mystery and its levels of play, both as an object and a quest, but is it truly the most difficult puzzle in the world? If you try it, let us know what you think, but no spoilers please. An Em Go! (Spoiler: That's an anagram for "Game on!")

For more puzzling information, see the next page.