To overstate the immense feat Wong Ho-chung just pulled off is impossible.

The 4 Deserts Atacama Race is one of the most diversely gruelling tests in the ultra-running circuit, as racers zigzag across the planet from climate to climate – from the Namibian desert to western China, and then down to the ends of the earth in Antarctica.

The race is so extreme TIME magazine named it one of the Top 10 Endurance Competitions in the world.

The four challenges are each around 250 kilometres, pitting racers against some of the most vicious deserts the planet has to offer, all in one year. There’s the Gobi Desert of western China, the Atacama Desert of Chile, the Namib Desert in Southern Africa and The Last Desert, which is a trek across Antarctica in sub-zero temperatures.

This year’s final leg featured 51 competitors, while the Namib and Gobi each featured more than 100 competitors, and the Atacama Crossing had 59.

Wong, who works as a firefighter in Hong Kong, just crossed the finish line in Antarctica over the weekend in first place, taking the 4 Deserts crown. He said the final, icy cold stage was easily the toughest for someone like himself used to running in hot, humid temperatures. He is one of eight members of the North Face Adventure Team and the six-stage race at the South Pole saw runners clocking in various kilometres from November 23 to December 3 which all begins in Ushuaia, Argentina.

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“I got a fever on day one,” said the 31-year-old who recently won the Male Trail Runner of the Year at the Gone Running Hong Kong Trail Running Awards. “Also my gear was not ready and I had no idea how to run in snow.”

From Argentina, racers take an expedition ship across the Drake Passage, and then set out on various courses over the Antarctic terrain using the vessel as a base camp.

The weather is so extreme in Antarctica, where temperatures can drop to minus-20 degrees Celsius on a regular basis, Wong said docking on the shore, and start times each day were determined by the conditions.

“I much prefer the hot climate and do not like racing in the cold. I did not feel like I performed very well in Antarctica, but I improved each day, it’s just so cold. I ended up getting a fever twice, and had to take medicine.”

One of the most gruelling parts of the wintry stage is the amount of gear each runner has to pack. There’s a list of 45 items each runner must carry with them which includes microspikes, glacier goggles and multiple types of socks and gloves. The bag can weigh up to 15 kilograms and Wong said there’s a few things that are a must.

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“I strongly recommend poles, some waterproof socks, and waterproof gloves. Also a big, big parka.”

Wong, who said he had been thinking about tackling the 4 Deserts since 2017, enjoyed the camaraderie he built along the way with the other runners. During the Namib Desert race in early May, he found himself running alongside Spanish runner Vicente Garcia Beneito. The two ended up chatting about life out in the middle of the desert, and ended up crossing the finish line together.

“He is an experienced runner,” said Wong, noting at one point the Spaniard suggested they slow down to enjoy the view.

As one of the most dominant trail runners in Asia over the past seven years, which includes wins at The Philippines North Face 100 and Hong Kong’s King of the Hills, Wong said the 4 Deserts was a bit of a shift in terms of racing style. The courses are so long and spread out, he said it became more about experience than actual times.

“It is more than a race, it is a multi-day journey of discovery in some of the worlds most remote places. And you develop a special kind of friendship with the other racers as you sleep and eat and live together for a week.”

North Face Adventure Team director Ryan Blair said the best way to describe Wong is a “calm but outgoing” family man who also likes to coach trail running. He said watching Wong train, and now complete such a historic feet is something extraordinary.

“To win the 4 Deserts Grand Slam comes only after years of focused effort and sacrifice to be the best you can be while pushing yourself to the absolute mental and physical extremes of what you thought was possible.”

Now that Wong is done, and has joined the elite 4 Deserts grand slam club, the obvious question presents itself: would he do it again?

“I am not sure, but probably not, because I would like to explore new things, to explore the world using my legs and eyes.”