The Hawaii Ironman World Championship’s wall has a name: the Natural Energy Lab.

In order to give readers a unique perspective of this year’s Hawaii Ironman, we’re going to look at some of the essential pieces that make this event special – be it a person, a group of people, or even a place—that makes the Ironman World Championship completely different from every other triathlon in the world. These are the parts of Hawaii Ironman that make it insanely difficult, incredibly inspiring and totally singular.

The wall comes for us all. As an endurance athlete, the wall can come at any time for anyone. For marathon runners and long-course triathletes, it often comes between miles 16 and 20 of the run. It’s a moment when no fancy sports drink or positive mental attitude or months of training can save you. Once you hit the wall, it’s just about finishing the course before the course finishes you.

The Hawaii Ironman World Championship’s wall has a name: the Natural Energy Lab.

Added to the Kona course in 1990, the Natural Energy Lab has the ugly distinction of being the worst thing at the worst time. After already flogging themselves for the previous 132 miles, athletes take a left-hand turn off the Queen K Highway into a bowl of heat. Completely exposed, and actually boasting some of the highest levels of insolation in the coastal U.S. (insolation is basically the strength of solar radiation that reaches the Earth), athletes enter The Lab at almost exactly mile 16 of the marathon. When they exit 3 miles later, they’re rarely the same.

NBC’s TV announcers like to memorialize an athlete entering the Natural Energy Lab like they’re entering the dark side of the moon. “Oh, he’s making the left-hand turn off the Queen K into the Natural Energy Lab! May God have mercy on his soul.” Going into The Lab evokes images of Eleven entering the upside-down in Netflix’s “Stranger Things”. Do athletes encounter a Demogorgon inside the Natural Energy Lab? What is the Natural Energy Lab, anyway?

Imagine a place where the U.S. government studies dark matter, near an active volcano, on a quiet Hawaiian island in the Pacific. Imagine Area 51 with secret sources of energy and aliens and nanoparticletubules. Imagine all of the weirdest sci-fi stuff ever written. Now forget it.

The reality is far less bizarre, but still pretty cool. In some ways, The Lab—or more accurately, the Natural Energy Laboratory of Hawaii Authority—is just an office park. There’s no top-secret government conspiracies at play (probably?). Instead, there’s a long list of environmentally focused tech companies that use The Lab’s unique location and facilities to conduct ocean-related research. No aliens. No Demogorgons.

The Lab has gigantic deep-water pipelines that pump cold ocean water up for tenants to study. It has giant solar panels to absorb those high levels of insolation that also fry athletes’ bodies and brains.

Just like everyone has a fun theory about what The Lab is, everyone has a strategy on how to beat it before it beats them. Coach Siri Lindley knows how to beat it—her athletes Mirinda Carfrae and Leanda Cave have had excellent experiences in The Lab, winning Kona four times between the two of them. Lindley’s strategy is to take the meanness out of the thing and turn The Lab into something beautiful, something empowering. Like Lindley’s outlook on many things, she finds the energy at The Lab magical. Her athletes train in The Lab. They practice in it. Lindley has them visualize how they want to feel entering the dark side of the moon, and how they want to feel popping out on the other end.

American Tim O’Donnell likens The Lab to the final round of poker—the moment when everyone has to show their hand. If an athlete is going to feel bad, it’s going to happen here, and it’s going be very big and very ugly. O’Donnell is no stranger to that nasty feeling. In 2014 his bluff was called in a very public way, and an infamous picture of him with his head down in dejection, hands on his hips, reminds him of how unforgiving The Lab can be.

Since then, O’Donnell has figured out a lot (his diet and nutrition, for one). In 2015 his plan was to run strong only coming out of The Lab, hitting the final five miles of the Queen K ready to go. This year, he’s planning on raising the stakes and putting in some serious work in The Lab, building through it and ramping up his intensity before he hits the Queen K.

For O’Donnell, The Lab really is like the “Stranger Things” upside-down world—a dark place where he has to dig into his body, mind and soul. If you lose in The Lab, you don’t come back. This year, his plan is to go further into the void than he ever has, accepting that it’s the only way to truly conquer Kona.