Colin O'Brady, 30, began his trek to the South Pole last week, skiing across Antarctica and officially starting the clock on his attempt at the Explorers Grand Slam. (Courtesy of Colin O'Brady/ )

At 6:55 p.m. Sunday, Colin O’Brady reached the bottom of the world. He planted his flag, snapped some photos and before long strapped back into his skis and left the South Pole. The clock had started on his journey.

Over the course of the next 51 / 2 months, O’Brady is chasing a record as unique as it is difficult, a nine-part adventure known as the Explorers Grand Slam. The journey officially started with Sunday’s successful trek to the South Pole. What follows is daunting. He must summit the tallest mountains on each of the seven continents and also trek to the North Pole. Just 44 people have completed all nine feats, and only two have done it in less than a year. O’Brady hopes to break the record, which stands at 6 months 11 days.

“I know it won’t be easy,” O’Brady said in an interview via satellite phone from Antarctica. “To set the world record is the goal and would be a dream come true, but coming back with all my fingers and toes and making it home safely is the priority.”

O’Brady, 30, is a professional triathlete who has competed in 25 countries over the past seven years. He has enjoyed the travel and the competition but still felt called to do something bigger.

“He got to a place where he realized that endurance sports are pretty self-serving,” said Jenna Besaw, his fiancee. “We looked around and thought, can we use his endurance and ambitions to create a greater impact in the community?”

He calls this incredible endurance challenge an “inspirational campaign” and he hopes to promote active, healthy lifestyles throughout his travels. He has partnered with the Alliance for a Healthier Generation and is accepting donations on his website ( to help fund programs that will combat childhood obesity.

“Triathlon for me was a dream come true, but this creates a platform that’s a little bit more interesting,” he said.

The journey itself is already paid for. Sponsors have taken care of costs associated with travel and the climbs, including all the gear. The final price tag is expected to be around $500,000.

O’Brady left his Portland, Ore., home on Christmas, flying to Chile and then Union Glacier in Antarctica. He started his trek Jan. 4 from 89 degrees south latitude, then over the course of nearly seven days, he skied the 69 miles to the South Pole — 90 degrees south. He did so hauling a sled loaded with his gear, at least 70 pounds in all, he estimated.

O’Brady has the next 51 / 2 months mapped out by the day. He’ll start with Mount Vinson (Antarctica, 16,050 feet) later this month and then attempt to scale Aconcagua (South America, 22,838 feet), Carstensz Pyramid (Oceania, 16,024 feet), Mount Kilimanjaro (Africa, 19,341 feet) and Mount Elbrus (Europe, 18,510 feet) by the end of March. He’ll trek to the North Pole in April before tackling Mount Everest (Asia, 29,029 feet) and Denali (North America, 20,310 feet).

O’Brady has climbed mountains most of his life, but the only one of those seven summits he’s previously reached is Kilimanjaro.

The first leg of the grand slam highlighted much of what was to come: extreme temperatures, camping on snow, isolation, fatigue. Skiing toward the South Pole, O’Brady didn’t seen any wildlife — or human life, outside of his trekking companions — in several days. The sun never set, and temperatures were consistently around minus-20 degrees. When his satellite phone froze, he stuck it in his sleeping bag to warm up before making calls home.

“It’s just a white abyss out here,” he said. “Loneliness and isolation is certainly a part of this. To me, that makes the journey more interesting.”

While he planted his flag in the snow Sunday, the more treacherous of tasks still lie ahead, none as challenging than Everest, where avalanches have killed 36 people the past two years. No one was able to summit the mountain last year at all. Even if conditions cooperate, the high altitude keeps many from reaching the summit, and the extreme temperatures impact many others.

“Mountains are in some ways inherently dangerous,” O’Brady said, “but any good mountaineer will tell you it’s all about assessing risk. You try not to put yourself in a situation that’s outside of your control.”

To make matters worse, he’ll attempt Everest in May — No. 8 of the nine feats on his quest — right after trekking to the North Pole. The North Pole is at sea level and will hardly help his body prepare for the altitude and thin air of Everest.

“There’s a lot of risk involved,” Besaw said, “but it really is about managing that risk out there. Barring some natural disaster happening, I’m fully confident that Colin has the skills and wherewithal to make the right decisions.”

The grand slam didn’t become a grand plan until about 18 months ago. O’Brady and Besaw were living in Spain, training for triathlons when pie-in-the-sky dreaming turned into actual scheming. They pitched sponsors, researched charitable causes and when they secured funding in late 2014, they began plotting out logistics in earnest.

O’Brady worked with a strength trainer back home in Portland, lugging a sled around the gym to prep him for his treks to the poles.

He continued competing last season on the triathlon circuit and climbed Manaslu in the Himalayas — the world’s eighth-tallest peak — immediately following a race to gauge how his body could handle back-to-back endurance challenges. While many Everest dreamers might spend months or even years preparing to summit the world’s tallest mountain, O’Brady will count the other summits on his journey as his Everest prep.

If all goes as planned, he hopes to climb Denali in Alaska in mid-June, completing the grand slam in less six months.