BAKERSFIELD, Calif. (KGET) — Dr. Bill Stone stresses there was only one thing motivating the team he led deep into the Cheve Cave in Mexico in an attempt to set a new record for finding a passage beyond a depth of 7,208 feet. They were all driven to make the grueling trek by a passion to explore.

“The first thing to understand is that nobody on this team does this for adrenaline.  This is not like a lot of other sports.  We’re there for the original exploration.  And that has its own rewards,” Stone says.

Their exploration of the cave can be seen with the newest chapter in the “Explorer” series from National Geographic – “Explorer: The Deepest Cave” – when it is broadcast at 10 p.m. May 30 on the streaming service of Disney+.

Those who shared Stone’s passion to go to new depths in the Cheve Cave included documentary director Pablo Durana, director of photography Kasia Biernacka and cave explorer Bev Shade. The three-month underground journey was a dangerous and highly technical adventure through more than 12 miles of tight, twisting passages.

Shade echoes Stone’s comments regarding the reason the team members got on board with the project.

“We’re super curious about what’s in there.  It’s so exciting to be the first person into a chamber or a passage.  And a lot of what I think all of us enjoy is this incredible teamwork that it requires to make it all happen,” Shade says.

Stone enlisted a team of 69 elite cavers that included expert cavers Sean Lewis, Corey Hackley, Sonia Dudziak, Victor Bravo and Gilly Elor from countries around the world, including Mexico, Poland, Slovenia, Canada, Sweden and Russia. During the dangerous and highly technical adventure, not only was the team trying to break the world record for venturing deeper than any other person on Earth, but the expedition’s other goal was to map everything as a way to create both traditional 2D maps as well as CGI 3D models relative to the surface topography so others can study the cave and discover what its future holds.

Taking a trip to the center of the Earth is very different from a trip to an uncharted island or jungle. Durana has been on numerous expeditions to collect footage for a documentary but he always knew with those projects that there was a chance of a rescue should something go wrong. That was not the case when they were underground.

There is no rescue organization that can retrieve somebody from the bottom of a cave this deep.  That meant the members of the team had to be trained in self-rescue capabilities.

“You have to realize that beyond a certain point, especially when you get out beyond Camp 3 in the movie, you’ll see lots of places where people are having to struggle through some sections of collapsed tunnel,” Stone says. “We have to be really mindful of that because if somebody broke a leg out beyond that, the likelihood is that we couldn’t get them out in any reasonable time.  And so you might have to, for example, set a leg and have it repair for a couple of weeks until the person can come out on their own.”

These kinds of realities come with a price Stone acknowledges there is always some fear when taking on such a project. But, that is not necessarily a bad thing.

He says the key is to know how to suppress fear.

“Having a little bit of it is good, but you have to focus and control to stay alive,” Stone says. “The only reason all of us are still here talking to you today is because we have that focus and the people who go down there have the same thing.

“So it’s a recognition and a willful suppression of fear that allows you to go forward because of your training, because of your experience.”

Exploring Cheve Cave offered some very unique challenges. Because it starts at 3,000 meters above sea level, there is not a large quantity of cave life. The conditions can become brutal at that high altitude where temperatures can dip to freezing but warm the deeper the team goes.

And, then there are the massive torrents of wind. They add to the danger but are also vital in guiding the team.

The “Explorer” series continues to search for answers to some of the greatest mysteries of history, science and adventure around the world. The first part of the anthology series, “Explorer: The Last Tepui” followed climber Alex Honnold (“Free Solo”) and a climbing team led by National Geographic Explorer and climber Mark Synnott. They were on a grueling mission deep in the Amazon jungle to help biologist and National Geographic Explorer Bruce Means to the top of a massive “island in the sky” known as a tepui to search for undiscovered animal species.