The Sahara Race is an extraordinary event. For seven days, runners chart a course through Africa's White Desert to the Sphinx in Egypt over 250 kilometres, alone for the most part as they forge their way through the sand and the heat and the hardships.
What is surprising, though, is that when you start talking to those keen - or mad - enough to take on the challenge you soon see they fail to flesh out the common image of an extreme-sport fanatic. For the most part, they are ordinary nine-to-five (or longer) human beings.
What may also cock an eyebrow or two around town is the fact Hong Kong is producing a stream of these 'ordinary' athletes who are facing up to and often beating the world's best.
Claire Price is a case in point. By day, the 38-year-old works in real estate. But come the weekends she can often be seen making her way through any one of the countless country park trails. And, after competing in adventure races and distance events in Hong Kong, she fancied her chances of tackling the Sahara.
In October, she headed out to Africa for the first time. And she came home crowned as the women's division winner in a time of 32:00:58, which was also good enough for fifth overall out of 60 entrants. It was the second time this year a Hong Kong-based woman had won such an event after Lucy Bong won the Atacama Crossing in Chile in July.
'I wanted to try something different,' she says. 'I had done quite a bit of adventure racing, I've done the Trailwalker a few times, which I love, and the King of the Hills series here which is great training for this kind of thing.
'After chatting with people here who had done the event I found it sounded well organised, exciting and something really different.'
Competitors in such events have to supply and carry all their own kit - apart from water and the tent that covers you at night, both of which are supplied by race organisers. Competitors run for as little as three hours a day and up to 24 hours depending on their pace and the demands of the conditions.
'It's a real case of mind over matter,' says Price. 'But the scenery is astonishing along the way. And you think of all sorts of things as you go along, about things at home and the race itself and what you are doing. And sometimes you can chat with other racers to help pass the time.'
As senior vice-president of RacingThePlanet Limited, Catherine Cole helps organise the Sahara Race - part of the organisation's 4 Deserts series that also takes in the Gobi March in China, the Atacama Crossing and The Last Desert in Antarctica. These races follow the same arduous, seven-day format as the Sahara Race.
'The idea is the races take in the windiest, coldest and driest places on earth,' says Cole. 'And the events attract a certain type of people. Mostly they are professionals, leaders in their communities. I hate to say Type A, but they are definitely people who are always on the go and looking for different types of challenges. The races were set up to take people to places they might never have gone on their own - remote villages and historical sites that might not always be there. So it's for people looking to go somewhere different, and those looking for a personal challenge.'
As Cole puts it, there is a procession of Hong Kong-based athletes lining up for the RacingThePlanet events each year. And almost in spite of itself, the city has proved the perfect training ground for this type of event - made even more popular in this modern media age where countless broadcast stations are searching for programmes to fill their air time.
'It's the challenge aspect,'' she says. 'That's why we get so many people from Hong Kong involved. A lot of them have never run a marathon and might either walk or half walk and run the event.
'Hong Kong is a perfect training ground. You've got the mountains, the outdoors right near where people live. So the endurance Hong Kong people have built up is ideal. Also there is the humidity here, the extreme temperatures really help people prepare.'
Rob James agrees. He finished third in the Gobi March in May - it was his first crack at such an event - and spent hours hiking through the Hong Kong hills as part of his preparation for that event.
'I was looking for something a bit longer than a marathon,' says the 41-year-old James, who is the Asian marketing manager for Manchester United. 'And I had spoken to quite a few people from Hong Kong who had done this type of thing and they all seemed like pretty normal people.
'I'm ex-army so carrying the pack and that doesn't really worry us. And with that in mind, I thought it was something I might be able to do and do quite well.'
Like Price, James had come to an age where he had both the time and the inclination to broaden his athletic horizons.
'It's something you do get better at as you get older,' he says. 'And most people at that age, you're at a stage in your profession where you have time to train again, the kids are grown up and you have more time to yourself again to look for challenges.'
He also believes Hong Kong played a major part in how he was able to adapt to the conditions of his race and meet the challenges thrown at him. 'Training in the heat all year round here really helps,' he says. 'And the humidity. Once you get to the races, your body is used to being stressed, it gets quite used to it.''
For 58-year-old Alasdair Morrison - who has completed all the races in the 4 Deserts series - the challenge came on two fronts. First, his wife, Mary Gadams Morrison, is the director of the RacingThePlanet series, so, he laughs, 'I guess you could say I felt obliged', and, second, there was the personal desire to take himself out of his comfort zone.
'These races tend to be 50 per cent physical and 50 per cent mental and that's when the older people tend to find their feet, you could say,' says Morrison, the CEO of Morgan Stanley Asia.
Family preferences aside, Morrison is one who believes the races seem to fit the needs of many ordinary professionals in Hong Kong.
'There's a great ethic in Hong Kong of work hard, play hard, so that helps,' he says. 'And then there's the money involved. It costs US$2,800 to compete and you have to get to the places on your own. And there are a lot of people in Hong Kong who can meet those needs and who are of the right age.
'By this stage in your life, you might have been to all the resorts and you have the time. Your family has grown up, or you don't have a family, and you are looking for a challenge that puts you outside your work environment. When you are there it's not the fact that you are a CEO or a chairman of your company, it's are you a good comrade in the camp site or are you a good comrade on the trail?'
For more on the series, see www.racingtheplanet.com