"I didn't feel pretty at all, so I was so happy when I saw how the pictures came out!" Ashley Schmieder tells PEOPLE

Ashley Schmieder and James Sissom went to great lengths (and high altitudes!) for their breathtaking wedding photos on Mount Everest.

The Sacramento, California, couple trekked up the world’s highest mountain, along with adventure-photographer Charleton Churchill, for an epic photoshoot set against gorgeous, snowy peaks.

“The photos are amazing and we’ll treasure them for the rest of our lives, but the experience also brought us closer together,” Sissom, 35, tells PEOPLE. “It was life-changing.”

“Awesome is a cliché,” Churchill tells PEOPLE. “But if it was re-introduced to mean what it really means, this is as close as you come under God to having a sense of awe.”

Credit: Charleton Churchill

Sissom and Schmieder are the first couple to wear a wedding dress and a tux at the base camp, adds Churchill.

And Schmieder, who wasn’t able to take a proper shower during the entire trip, used face-wipes to clean herself. She did her own make-up on a small compact mirror in their tent prior to the photoshoot.

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“We joked when we got back, I was like, ‘I feel like I’m the ugliest bride ever!’ ” Schmieder, 32, tells PEOPLE. “We hadn’t showered in a week and dry shampoo would not touch my hair. I didn’t feel pretty at all, so I was so happy when I saw how the pictures came out!”

Schmieder, an executive assistant in corporate health care, had been following Churchill on Instagram for years and reached out prior to her nuptials with Sissom, a bartender, to see if he’d work with them.

Credit: Charleton Churchill

“We had planned to go to the Bahamas and get married,” she says. “But Charleton knew we were capable of doing Everest and just threw it out there like, ‘Would you guys go to Everest to get married?’ ”

The couple, both avid backpackers and hikers, were up for the challenge.

Schmieder and Sissom trained for nine months in Sacramento, building up leg strength on their gym’s StairMaster and developing endurance on day hikes to Lake Tahoe.

On March 5, they flew to Kathmandu, spent a night at a yak and yeti hotel and began preparing for their major trek.

Credit: Charleton Churchill

Through a company called Mountain Madness, they booked three sherpas — an English translator, a lead guide and a chef. They were also provided three porters to help carry their duffle bags. In order to make sure Schmieder’s dress and Sissom’s tux remained wrinkle-free, they carefully folded the items into a cardboard box carried by a porter.

They stopped at various towns along their 10-day trek along the Mount Everest Base Camp Trek, visiting with monks and locals before reaching the spots where they took the wedding photos.

“There was one particular day we hiked in 3 feet of snow,” says Sissom. “That was an unexpected storm and the sherpas hesitated to let us go because the snow was so deep and we had to go along a steep cliff.”

Credit: Charleton Churchill

The group began experiencing altitude sickness about 14,000 feet up — enduring headaches, loss of appetite and nausea.

“James had a really bad cough, dry, deep, and painful, where he could barely breathe sometimes,” recalls Churchill. “I got food poisoning and that messed me up for a few days. The cold was the worst part, having to suffer in the cold…”

The sherpas brought along bottles of oxygen for the team and had antibiotics and a first-aid kit on hand for emergencies.

Credit: Charleton Churchill

During the shoot, temperatures ranged from minus 5 degrees to 5 degrees.

The conditions may have been less than desirable, but the photos look incredible.

“It was really cold but you can’t tell, I do have two pairs of pants and two pairs of socks on under my dress,” says Schmieder. “I was just thinking ‘Let’s do this as long as I can bare it!’ ”

They would shoot for 10 minutes and then take a break while Schmieder warmed up with a down jacket.

“I said to myself, ‘We’re never going to be here again!’ I wanted to push myself as much as I could while still being safe,” she says.

Credit: Charleton Churchill

Due to regulations in Nepal, the couple was unable to actually get married on the mountain, so instead they exchanged vows and rings. And on their way up, they received a blessing from a monk.

“This was a beautiful moment we shared together to start this union,” says Sissom. “It was romantic starting a life together through pain and struggle.

“But most of all it was life-changing and so, so beautiful.”

Credit: Charleton Churchill

Churchill says taking the wedding photos on Mount Everest was like “making a documentary.”

“Photographing the highs and lows, the dirt, the pain, the joy… I felt like I was on a mission to tell a story,” he adds. “Standing before epic mountains as we were on the wedding day and throughout the trip was just crazy amazing. And finally arriving to base camp tired, beat up, cold, lacking oxygen, was really difficult to just sit down and stare and take it all in, but with all the mountains surrounding the area, it’s just so beautiful.

“Once they exchanged vows, there was happiness, it was bright, but they took off their glasses and looked into each other’s eyes with all sincerity. Capturing them with the Khumbu Ice-fall behind them was just unreal, and in a wedding dress in below freezing temperatures, even with the sun up.”

Credit: Charleton Churchill

The couple is now back in Sacramento “still recovering” from their epic adventure journey.

“For us it was cementing our love amongst these incredible little moments,” says Sissom. “Like we saw snow leopard tracks in the snow, and how many people can say they did that!”

Credit: Charleton Churchill

Schmieder and Sissom hope to take their honeymoon next year.

“Somewhere tropical and relaxing!” says Schmieder with a laugh. “But this Everest adventure has brought us so much closer, it was amazing.”