(CNN) - Half a million athletes directly competing against each other on a level playing field at the same time. A logistical and practical impossibility, right?
On February 22, in an event known simply as "the Open," an estimated 500,000 CrossFit athletes from all over the world will begin a five-week fitness competition, which will test strength, endurance, and aspects of gymnastics.
The Open works like this: every Thursday at 8 p.m. Eastern, a set workout, kept secret ahead of time, is released live online. Everyone, then, has four days to complete it in front of a judge or on tape and to submit their scores. Simple.
After five weeks the top few hundred in the world advance to the next stage of competition, eventually working towards the CrossFit Games in August. The other 99.9 percent however, go back to the drawing board -- or, in CrossFit terms, the whiteboard.
From 30 competitors to a global phenomenon
In recent years, the Open has become truly global with competitors participating from every continent, including Antarctica and at sea. But it wasn't always this way.
The competition began back in 2007, when CrossFit founder Greg Glassman visited the family ranch of one of his employees, Dave Castro.
Glassman was already making a name for himself for the new workout practices he was putting into place, fostering a sizable following online, and suggested to Castro they hold an event and make it "the Woodstock of Fitness."
From that, the CrossFit Games were born.
With just 30 competitors in its first year the event quickly flourished, eventually outgrowing the ranch. Then, just a few years later it was selling out arenas. During that time the qualification pool grew equally as rapidly, adding regional qualifying events in 2009, and by 2011 the introduction of the worldwide Open.
Within a matter of years the CrossFit Games had expanded from a Californian curiosity to a global phenomenon, annually crowning what CrossFit calls the "Fittest on Earth."
The top secret facility
CrossFit's reputation as a "cult", simultaneously with trepidation from the outside and strong affection from within, is not diminished by the secrecy surrounding this competition.
Part of Glassman's original creed of CrossFit was to prepare athletes for anything, "not only for the unknown but for the unknowable," and as such, the weekly workouts are kept top secret.
Athletes expecting to advance beyond the Open must prepare for every possible eventuality, and any beforehand knowledge of the specifics of the competition would create a massive unfair advantage.
Therefore the competition is created and tested at an undisclosed location where prior to our arriving, no outside media had ever been given access.
In a nondescript industrial park, behind an unmarked door we found Dave Castro, director of the CrossFit Games and a former Navy SEAL, who closely protects his work with the discipline of a security guard at Area 51.
We were driven to the gym blindfolded and the location data was scrubbed from pictures and videos taken within the facility. All confidential information pertaining to the competitions seen on camera had to be pixelated before going to air and both my photographer and I had to sign non-disclosure agreements.
The gym itself is a miniature version of the competition floor at the CrossFit Regional and Games events.
The walls are plastered with equipment used at previous years' Games, as well as equipment being tested for future competitions which, of course, is forbidden for me to talk about.
In addition to testing workouts Castro uses the facility to design each competition -- behind a locked door to which only he has the key -- where no other CrossFit employee is allowed.
After some deliberation Castro agreed to give us a brief tour of his secret room, but told us not to look too closely and swiftly ushered us out.
While he insists on keeping everything tightly under wraps, Castro cannot help but issue tantalizing hints on his Instagram account. Often seemingly random, always cryptic, and sure to cause a swarm of online activity among the CrossFit obsessed.
Castro, in a rare interview he granted CNN, insists that none of his hints are deliberate red herrings and that every post relates to a workout -- at least it does to him.
"People really enjoy speculating," Castro says. "Sometimes I'll see something and it will remind me of the workout. I'll see a fire hydrant and it will remind me how I felt after I did the workout, so I'll take a picture and post it and people will go crazy speculating on what it can be."
The actual workouts will remain secret -- that is until they are announced on a live online broadcast.
In what has evolved to become a highly produced roadshow hosted in a different international city every week, Castro will write out the workout on a whiteboard before an increasingly large and fervent studio audience. He will then be joined by some of the best CrossFitters in the world, including many of the former "Fittest on Earth" winners, who will step up to become the first to take on the challenge, live online.
Then it's the rest of the world's turn.
The no-nonsense authoritarian taskmaster
Within the CrossFit community Castro has garnered somewhat of an interesting reputation.
His name has become synonymous with a degree of difficulty considered by many as above and beyond the norm for CrossFit, with a sizable number of people proudly wearing potentially offensive t-shirts proclaiming "Dave Castro is a pr**k."
Instead of taking it personally or shying away from the remark, Castro accepts his reputation.
"That actually started before my CrossFit career when I was a Navy SEAL instructor, because I was preparing these kids for war," he said.
"I'm not trying to be their friends. That was my mentality then and it kind of is my mentality now. I'm testing these athletes to find out who the fittest in the world is and I'm not trying to make friends."
In person, Castro is amiable and engaging, leading me to believe his no-nonsense authoritarian taskmaster persona is largely a front, a workplace necessity when running a sport jam-packed full of alphas.
Compete directly with the best athletes in the world
The Open has become a focal point for the CrossFit community offering an opportunity to measure your personal progress since last year's competition.
But the event also has another feature, and one which is perhaps unique within the sporting world.
Unlike most, if not all sporting events, the Open provides an opportunity to compete directly with the very best athletes in the world. No matter how good my tennis game is on any given day, I would never have the opportunity to go head-to-head with Roger Federer or Rafael Nadal.
However, in theory (very much in theory), on your best day in the Open you could come out on top against the athletes who will eventually go on to compete in the sports' world championships at the CrossFit Games in August. Just as equally, if you continue to perform well, you could join them there.
This is unlike any other sporting event because no professional would ever begin their championship campaign at the same round as weekend warriors and enthusiastic amateurs.
More realistically though, this system of direct competition allows you to go head-to-head with friends, colleagues and family, which makes the Open a true coming together of the CrossFit community.
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