The Grand Canyon has a way of making you feel insignificant, with its sweeping vastness and breathtaking views. Its walls stretch for miles, with the Colorado River snaking through it, but looking like a trickle from above.

A group from Hawai'i decided it would be a great idea to run it.

The aptly, yet unofficially, named Rim-to-Rim-to-Rim trail, which, for this group, started at the Bright Angel Trailhead, went down to the bottom of the Grand Canyon and then back up to the North Kaibab Trailhead — traversing 20-plus miles one way with a nearly 6,000-foot elevation change — and back the same way.

"Some of it was the challenge and adventure of it," Craig Wagnild said. "There was excitement to do something we had never done before.

"There was a camaraderie and each of us pushed each other to try and do better and all of us wanted to be a part of it. It was something we will all look back on for the rest of our lives. It was some of the most beautiful sights I had ever seen, with the sun coming up, and the sun going down."

The group included Bob Dewitz, 54, the CEO/President of Hawaii Select Investments, Inc.; Bill Byrns, 51, attorney; Joe Gromwald, 41, a financial adviser; and Wagnild, 41, an attorney. All are avid distance runners, be it participating in double-digit marathons, ultra marathons, Ironman competitions or Haleakala's Run to the Sun.

"We never ran into (a group) from Hawai'i who had ever done it or knew anyone who did it," said Wagnild, who said they actually crossed paths with a group from California also attempting the task.

Yet the Rim-to-Rim-to-Rim run surpassed anything they had attempted before.

The 48.5-mile trek lasted 18 hours, 50 minutes, and all of the months of carefully detailed planning and training prepared them well, but not enough for the unexpected.

That included landslides and the inevitable wait for mule tours. But while exhaustion and dehydration threatened to put a damper on their experience, in the end it was "a very uplifting experience in human potential," Dewitz said. "You can do anything if you plan for it and if you prepare for it. The fact that all four guys finished is a testament to that."

Friends for years, some longer than a decade, the suggestion first came up after Dewitz and Byrns read about others doing it in UltraRunning Magazine.

"There was a story about a group of women who did it, but only did it halfway," Dewitz said. "It was more like, 'Gee that would be a neat thing to do.' Then the ego stepped in."

Vast resources online guided them in their planning. Following the advice, the group trained by running five to six times a week. About four months out, they were running four to five hours a day for 20-plus miles. Leading up to the big event, it increased to five or six hours a day on weekends.

"Doing the run is the reward for all the training," Dewitz said.

They started out at 4:30 a.m. May 16, hoping to maintain a 15-minute mile pace on the way down the trail. Their starting point was at an altitude of 6,850 feet, and as they made their way down, their pace quickened to 10-minute miles at certain points.

"A lot of us were nervous we would push too hard and wear ourselves out," Wagnild said. "As a result we hit the toughest area of the course at the toughest time."

That was the incline up to the North Kaibab Trailhead, which rises to 8,250 feet (the lowest point they traveled was approximately 2,400 feet). Meeting them at that halfway point were family and friends to who provided support and — even better — hamburgers.

"At that stage, not only were we exhausted and somewhat dehydrated, all we had been eating were gels or Powerbars or the equivalent," Wagnild said. "All of us wanted some solid food. Just having a greasy cheeseburger was the best thing in the world."

Or as Dewitz put it: "It was like heaven had descended and someone put new lives into our bodies."

The meal and hour-long rest rejuvenated the group as it made its way along the same path it traveled before.

Months and miles of training could not prepare them for the elevation changes or the dry heat.

"It was very hot, and as we got down into the canyon it just got stifling hot, because there was very little breeze," said Wagnild, who said temperatures reached 100-plus degrees.

Problems with dehydration — there were multiple water stops along the way to refill their water bottles but little answer to when their bodies stopped absorbing the water — slowed them as it began to get dark on the return trip to Bright Angel Trailhead.

Darkness required the use of headlights, a necessity when paths were three to four feet wide, with 1,000-foot drops on one side.

"As you go through the run each of us had points of 'Why am I doing it?' and at the end you say, 'That was pretty great,' " Dewitz said.

While the path was well-worn because of the frequent mule rides to the canyon's bottom, those same caravans presented problems for the runners.

"Fortunately we left early enough and didn't encounter any going down," Wagnild said. "But going up, we had to stop, and the dust was just choking. It made a tough climb even more unpleasant."

At one point on the return trip, they were interrupted by a landslide.

"Some time between 10 and 10:30 p.m. we were working our way up the South Rim, at that time it was pitch black and we were operating with our headlights," Wagnild said. "It was a sheer drop down, but you can't see because it is so dark but you can tell. At one point we heard a rumble and felt these little rocks falling. I just laid myself against the rock wall. Then this huge rock landed where I was standing just before. All of us were in shock."

Thankfully at that point they had only about an hour remaining in their journey, and finally emerged from the Canyon at 11:20 p.m.

Again, waiting for them was their support group, which was ready with cream of broccoli soup.

"You couldn't choke cream of broccoli down my throat right now, but then it was the best thing we had ever had," Wagnild said.

Both Dewitz and Wagnild said the experience was amazing and they would recommend it to others but neither would try it again ... for different reasons.

"I don't know," Wagnild said. "Maybe we're too close to it. I don't know if I'd do it again, because I think we have a limited number of things in our lifetime."

Dewitz, on the other hand, has other things in mind.

"I've been reading about Machu Picchu," he said.