"When I was 1 year old, my dad moved my family out to Colorado to be near the mountains where there was more stuff to do," he said.

For the next 25 years, Juergens was cold, wet, dirty -- and happy.

"We did pretty much everything outdoors you could do when I was a kid, and after high school I started climbing 'fourteeners,'" he said of Colorado's 54 peaks that soar over 14,000 feet. "I would climb three mountains a week. It got to the point where I was never home."

He froze his fingers enough times that he never again forgot gloves. He earned a college degree in mapmaking. He learned weather patterns, orientation and knot tying.

It was ordained entertainment.

"God had that planned out," Juergens said. "I understand exactly why I have been brought up and raised the way I am. God knew who I was when I was a little kid and He knew who I'd be today."

Today, Juergens hikes the "roof of the world," battling freezing temperatures, adapting inadequate maps and running from lightning storms.

His suffering is countered by the rewards of reaching people who have never heard the Gospel.

"Not all people live in the cities where you can take a taxi to their front door," Juergens said. "People live in places that we would never dream of living in but the fact is they live there. That's where they're put and they're not coming to us. We have to go to them."

He and his teammates do just that. It's a tough job even for Juergens. People get sick from the altitude and the food. Travel is grueling. The spiritual warfare is intense.

John Costa*, Juergens' team leader, said it takes five days to reach a village from the city.

"It's a multiple-hour bus ride into the mountains and then you have to spend a couple of days in a base town acclimatizing before you can start to hike or mountain bike out," Costa said.

The ridges to climb are between 10,000 and 15,000 feet, interspersed with valleys. Vicious dogs and giant oxen, yaks, are not uncommon. The air is thin and cold.

But the struggles are inherent in a trek to an unreached people who are, Costa said, simply hard to reach.

"There are a lot of people out there that if we want to actually walk through their front door and share the Gospel with them, we're going to have to use our feet or a bike," he said. "And the obstacles aren't just geographic -- they're physical, spiritual and political."

Each unreached people group has its own challenges -- language, hostile terrain, security or accessibility, Juergens said.

"If you don't like the cold or you don't like inclement weather or you're afraid to get tired and sweat or if you're afraid your makeup's going to run or you don't like how your hair looks when you're tired, this isn't the job for you," Juergens said. "Climbing mountains isn't easy. They don't climb themselves."

And mountains can be deadly.

Severe altitude sickness hit one team member on a ridge recently and it took 14 hours to evacuate him. Costa and Juergens took him down the mountain in a trip that first utilized villagers' horses, then a borrowed car, and then a hired car to reach the hospital.

"We had to pull off a rescue," Costa said. "We take great care not to let that happen. We push to the edge, but it's a calculated risk. We are compelled to reach these people, so we want to put significant effort into it."

The mountains can be unpredictable and certain issues can make the terrain difficult to access, including the denial of permits, civil unrest and travel restrictions. In some areas, foreigners aren't allowed.

"We are seeing more questioning than ever before but the Gospel is advancing more than ever," Costa said, noting that the spiritual warfare is producing spiritual fruit. "The two go hand in hand."

Progress is slow. Continued...