Mark, from Newburgh, conquered North America's highest mountain, Mount McKinley, last Wednesday (June 17), according to British Summer Time.

However, according to Alaskan local time, the 26-year-old actually reached the summit of the 20,320ft peak on Tuesday, June 16.

For Mark, who broke the world record for pedalling around the world, it was his first major challenge on his latest adventure.

The Mount McKinley climb is only one leg of an eight-month journey which will see him cycle from Anchorage, Alaska all the way to Ushuaia at the southern-most tip of Argentina, climbing the highest peak in North and South America along the way.

This season only 50 per cent of those who have attempted Mount McKinley have actually reached the summit (source: US National Parks Service).
After 15 days of climbing, Mark's bid for the summit involved some incredibly dangerous challenges.

He explained: "After 10 hours spent fighting towards the top, with blue sky all day, we were suddenly faced with a massive snowstorm as we approached the summit.

''We crossed a narrow arete with a drop of thousands of feet on either side, with very little visibility due to the blizzard."

Once at the top it was clear the group could not stay in the 'white-out' conditions for long. For just two minutes, and still with zero visibility, Mark stood atop Mount McKinley at 20,320 ft.

He said: "If it hadn't been for the marker at the top, which shows the altitude, I wouldn't have known where I was."

This has been a completely new challenge for Mark and has really pushed him to the limit.

He remarked: "It was epic. It was the scariest mountaineering I have ever done. As far as an adventure, it was everything I could have hoped for."

In total, it took Mark 15 hours and 45 minutes to climb from high camp, at 17,200 ft, to the summit, and back again.

Unlike the rest of the team who reached the summit, Mark couldn't rest for long as he still has 15,000 miles to cycle and another 22,841 ft mountain (Aconcagua in Argentina) to climb.

"This is the first part of a seven-month expedition for me so it's a great relief that it's gone well." Mark said.

"I love it up here, don't get me wrong, but it's been an incredibly difficult mountain and I'm quite looking forward to being back on my bike."

Mount McKinley is also known as 'Denali' — meaning 'The Great One'.

From base-camp to summit, the ascent on McKinley at 20,321 ft is the longest of any mountain on earth — even Everest is not as far, even though it is higher.

Mount McKinley is one of the 'Seven Summits'; the highest mountains on each of the globe's seven continents.

The expedition to climb Denali has pushed Mark in new directions as an adventurer. He is used to making his own decisions, being active and constantly on the move on the bike.

This kind of mountaineering is a slow laborious team-based assault on the mountain and he had to change down a few gears.

Mark was led by two guides and accompanied by five other climbers.

Unlike other peaks there were no porters, the group had to carry their kit up the mountain in a series of stages.

This was not a straight A to B journey, the group spent much time gaining altitude and then descending in order to acclimatise — effectively climbing the mountain more than once!

Mark explained: "A lot of that time is spent acclimatising and it's one of the coldest mountains on earth to climb up so it's been a difficult one."

Mark joined this mountain expedition after many months of being busy with training, expedition preparations and public engagements.

He found it very strange to stop every day and to take so much time to rest and acclimatise at altitude.

McKinley stands Mark in good stead for his next climb, Aconcagua in Argentina, which he'll reach after pedalling 13,000 miles. Aconcagua is the highest mountain in all of the Americas (North, Central and South).

Mark will now descend quickly as he is eager to get back in the saddle and head for the Alaskan, USA/Canadian Border.

Once into Canada he'll head south through vast, wild and sparsley populated territory, where isolation could be a huge challenge. Along the way he'll pass 'Gold Rush' territory and will see some of Canada's most stunning mountains and prairies.

He will travel through 15 countries along the Cordillera which runs from Anchorage through the Alaskan Ranges past the Rockies to the Andes, finishing his journey in Ashuaia at the southern tip of Argentina, in February 2010.

Mark is posting regular updates, blogs, video and photos to a dedicated website on bbc.co.uk/cyclingtheamericas and telling the story in social networks including Twitter, Flickr, Facebook and Bebo.

A GPS Tracker will also allow visitors to the website to follow him on every part of the journey.

BBC Scotland is producing a three-part series, 'The Man Who Cycled the Americas' for broadcast on network BBC1 when the journey is complete.

Greg James, on Radio 1, is catching up with Mark regularly via satellite and telephone (you can hear interviews by visiting bbc.co.uk/cyclingtheamericas).

Mark will also be appearing on BBC 'Breakfast' at various points along the route.