During the course of the expedition, Mr Williams landed a seaplane on the Amazon to get to the world’s largest city not reachable by road, and met a community living in the shadow of an active volcano.
But perhaps his most extreme venture was Siberia – the first episode of the show’s second series – where he discovered just how dangerous it is to fly in one of the coldest regions on Earth.
Mr Williams, an exceptionally warm and down-to-earth character, tells MailOnline Travel: ‘There were certainly some of the toughest conditions there that I’ve ever faced, with temperatures of -50C.
‘When things go wrong out there, they go really wrong.’
After flying over a giant open-cast diamond mine in the town of Mirny, five times deeper than the white cliffs of Dover – so deep it creates its own weather – he reaches Oymyakon, the coldest inhabited place on earth.
But on the lake, something goes badly wrong.
A helicopter carrying production crew crash lands on a bank of thick snow, shearing off its tail rotor mere feet away from Mr Williams and throwing chunks of ice at him and his group.
Heading up a new three-part Channel 4 series, Mr Williams’ travels have taken him to Siberia (pictured) where he braved freezing temperatures and witnessed a terrifying helicopter crash
He took up flying after he was paralysed from the waist down in a devastating car crash eight years ago
‘I was just in shock,’ he recalls upon witnessing the crash, which miraculously injured no-one. ‘But that’s the culture in Russia, they just don’t care. Wearing a seatbelt in a car is seen as an insult to the driver.’
Mr Williams and his crew refused to fly again with the local airline responsible, and were now faced with a nightmare scenario – stranded in the vicious cold with no wings.
Without the helicopter, the team’s only route to their next destination is a six-hour drive across ice roads. They travel on to meet Mikhail and Tatiana Itelgelov, a couple who live off-grid and breed Siberian horses.
Mr Itelgelov takes Mr Williams on a sleigh to help round up his horses, and introduces him to his staple diet: frozen raw horsemeat.
The meat itself, he says, was ‘nice’ – a richer-than-beef taste – but their other prized delicacy was another matter.
‘Large horse intestines stuffed with a blend of blood and milk,’ he reveals. ‘It was utterly vile, but I had to put on a brave face.’
Over a frozen lake, a helicopter carrying production crew crash lands on a bank of thick snow, leaving them stranded. Pictured, Mr Williams prepares to disembark a separate aircraft
Mr Williams (pictured) tells MailOnline Travel: ‘There were certainly some of the toughest conditions there that I’ve ever faced, with temperatures of -50C’
Asked whether Mr Williams’ wife, who he married last November, worries sick about his close-calls with danger, he says yes.
‘She’s like my mum, so I’m used to it,’ he remarks. ‘Generally I don’t go into detail about what my trips consist of in advance, and I don’t tell them about the mishaps until I come home.’
A good example?
Flying into a Peruvian goldmine in the Andes by undertaking one of the world’s riskiest landings.
‘We had to corkscrew into a narrow canyon before making a sharp left turn,’ he explains. ‘The pilots used a cactus perched on the ridge as a visual reference point.
‘Not normal operations for an aircraft of that size, or indeed any. It was good fun though.’
Another, albeit less knuckle-biting highlight, was visiting the South Pacific island chain of Vanuatu, with flying doctor Mark Turnball.
‘That was exhilarating,’ he says of the experience, which saw him follow Dr Turnball on his daily rounds during which he is roped in to a spot of bush dentistry, pulling teeth without anaesthetic.
Investigating the South Pacific islands of Vanuatu, where he explored with flying doctor Mark Turnball
Mr Williams in front of a demolished house on the island of Koro in Fiji, following a severe cyclone
And perhaps the most unusual place he saw?
A community living on the island of Tanna in the shadow of an active volcano who have created a new religion, based on the American pilots who landed on their Pacific island before the Second World War.
He says: ‘They are one of a group of island communities who make up the “cargo cults” – because they are so isolated from the outside world, they’ve never been influenced by mainstream religions. So they have formed their own.’
He adds: ‘They believe that a pilot from the Second World War – “John from America” – came and banished the Japanese. He left them with some military uniforms and to this day, every Sunday they dress up and parade around the village square in honour of him.’
With filming wrapped, Mr Williams will next be off to Rio to host the 2016 Paralympics for the second time for Channel 4.
‘I can’t wait to get in amongst it all, we’re right in the centre of the park this year,’ he says. ‘It’s rare we get to see all these amazing athletes come out and show us their craft.’
The first episode of Flying to the Ends of the Earth airs on Sunday July 31 at 8pm on Channel 4.