Clinging tightly to the edge of the cliff, not daring to think about how many hundred metres he was from the ground, TV presenter Nick Knowles took a deep breath and conquered one of his biggest fears.

Travel, he admits, invites everyone to step outside their comfort zone. And there’s no platform better than national TV to broadcast the results.

Knowles was in Chile, at the very bottom of the world, for his new three-part series Nick Knowles in South America, which airs on Channel 5 from June 5.

“A lot of what Torres del Paine is about is climbing,” explains the 61-year-old, describing the Patagonian national park famous for its pretty but perilous peaks. “So I thought to myself, there’s no point talking about it if I’m not going to do it.”

Although his sympathetic director repeatedly offered to find an alternative way to tackle the filming, Knowles insisted this was now a battle of “me versus me”.

Shuddering at the memory, he recalls gripping the rock with his fingernails.

“I’m roped up, but I’m 19 stone and my climbing partner – who is supposed to be my counterweight – is about nine stone wringing wet! But even when I’m shaking, I’m still looking out and thinking this is incredible. We can’t let fear stop us from doing things.”

Later in the series, he goes on to play polo with a professional Argentinian team (“They gave me this feisty pony who took me for a ride”) and picks up a few tango steps in Buenos Aires (“Just to do it there is fabulous. Even if I did It badly, I don’t care”).

The series also shines a spotlight on several extraordinary environmental projects and success stories, reflecting Knowles’s belief that long-haul travel can still be sustainable. “As part of these programmes, we want to showcase things that bring hope,” he explains. “We have a bit of a nihilistic attitude towards the environment, but there are people doing extraordinary things.”

In this series, he visits farmers feeding seaweed to cattle to reduce methane output and meets brewers using CO2 waste, water and wind power to make fuel.

“Humans are very destructive monkeys, but we are also very creative monkeys too.”

Visiting Argentina and Chile had long been a bucket-list ambition for the former rugby player, journalist and game show host, due partly to a boyhood obsession with great explorers.

“Knowing the stories of Darwin, Drake and Magellan, and being in the Strait of Magellan between Tierra del Fuego and the mainland was amazing to me,” he recalls. “In Punta Arenas (the main city on the mainland) there are replicas of Magellan’s ship Nao Victoria and Darwin’s HMS Beagle. Considering the difficulty of those waters, the boats seem very tiny.”

The reason Tierra del Fuego (land of fire) was given its name, he tells me, was due to the hundreds of fiery pinpricks spotted by explorers in the darkness – all from cooking fires on boats belonging to the Kawesqar people.

Meeting descendants of that indigenous population evoked mixed feelings.

“It was enlightening and inspirational but at the same time a little sad,” he confesses. “In Chile, they use the symbolism of the Kawesqar quite a lot – there are streets named after them and there are statues in ceremonial garb – but the people themselves, who were a nation living on boats, aren’t allowed to fish because they can’t get permits. And that strikes me as odd. They’ve become land-based and as a result that culture is disappearing.”

Legends and traditions are, however, still very much part of the social fabric that binds communities together in the Chiloe islands, an archipelago off the west coast of Chile. While delving into stories of witchcraft, Knowles was granted an audience with a white witch inside one of the islands’ famous wooden churches. “We were chatting away, and she told me, ‘You do know it’s all about reading omens. For example, that vulture that’s just landed on the church is looking at you’. I thought thanks very much!”

Not all wildlife he witnessed on the journey, however, was quite so ominous. In Tierra del Fuego, Knowles joyously recounts searching for Magellanic penguin chicks in their burrows. Seeing them, he says, seemed almost unreal – a sensation he’s experienced on several occasions throughout his lifetime and one he believes is the very essence of great travel.

“When I was young and I went to Australia on my first big trip abroad, I suddenly stopped dead in my tracks when I saw oranges on the tree. Another time, I was amazed by all these rainbow lorikeets but couldn’t work out who they belonged to.”

Having grown up looking at starlings, sparrows and blackbirds, he simply couldn’t compute the idea these colourful birds might be wild.

“I try to make sure I hang onto a little bit of that wonder,” he says, recognising his own opportunities to travel have been a privilege beyond most viewers’ dreams. “I want to to be able to look at a penguin and think, ‘Oh my God! It’s a penguin… and it’s doing penguin things.”

Nick Knowles in South America airs on Channel 5 at 7pm on June 5, 6 and 7.