To mark International Mountain Day, we're paying homage to (probably) the coolest person on Earth right now. Here's why we love him:

1. He was the first man to climb every mountain over 8,000 metres

There are 14 peaks on Earth with summits in the "death zone", above 8,000 metres (26,000 feet). Just over 32 years ago (October 16, 1986), the Italian Reinhold Messner, at the age of 42, became the first person to climb them all.

2. And he conquered them all without bottled oxygen

Messner has long been a supporter of "alpine style" mountaineering, which involves minimal equipment (no satellite phones, no fixed ropes, no established camps) and little or no external support, as he believes standard "expedition style" climbing is disrespectful and damaging to nature.

In 1978, he and Peter Habeler became the first people to climb Everest without bottled oxygen, despite dozens of doctors and specialists claiming it wasn't possible.

“I have done 2,500 climbs in the Dolomites. They are for me still the most beautiful mountains in the world,” he told Telegraph Travel last year. And the most dangerous climb of his life? The middle pillar of Heiligkreuzkofel, a 600m wall in the region. “I was 23 years old, my brother Günther was 21,” he added. “We slept on an overhang. There were no holes [to insert a piton], nothing. I felt trapped. Below me was an abyss. Somehow I did it but nobody believed us. For 10 years, people said it was a lie, until someone else finally did it and he found my piton. That was the most dangerous situation of my life.”

Messner re-wrote the climbing rulebook Credit: 2006 Getty Images/Keystone

3. He reached his first summit aged five

At an age when most people are still scared of the dark, Reinhold Messner was scaling peaks in the Dolomites, like the 11,000-foot Geisler near his birthplace of Brixen. By their early twenties, he and his younger brother Günther were already among Europe's best climbers.

4. He was the first person to summit Everest solo

In 1980 he returned to the top of the world with only a Himalayan monsoon for company. He took everything he needed on his back and was up and back in four days. "Climbing Everest solo was the hardest thing I've done," he recalled in an interview with The Guardian in 2003. "I was alone up there, completely alone. I fell down a crevasse at night and almost gave up. Only because I had this fantasy - because for two years I had been pregnant with this fantasy of soloing Everest - was I able to continue."

The achievement "was like landing on the moon," according to Conrad Anker, 39, an Everest veteran from Bozeman, Montana. "After that, everything else kind of pales in comparison."

“You feel your exposure, especially at night,” Messner told Telegraph Travel. “They say only children are afraid of the dark. Bull----. Grown men, too. Me, too.”

5. And was the first person to conquer numerous other peaks

His catalogue of other first ascents is remarkable. They include:

Nanga Parbat Rupal face

Heiligkreuzkofel middle pillar

Marmolada south face

Marmolada West Pillar

Furchetta west face

Yerupaja east face

Yerupaja Chico

Agnér northeast face

Mount McKinley, "Face of the Midnight Sun"

Agnér north face (first in winter)

Furchetta north face (first in winter)

Droites north face (first solo)

6. He wasn't bowed by tragedy

His first ascent of an eight-thousander, Nanga Parbat in 1970, was a tragic success. Both he and his brother, Günther, reached the summit – but only Reinhold made it down alive. Reinhold went back in 1971 to find Günther’s remains, but was unable to do so.

7. Or the loss of six toes

Though he survived the climb of Nanga Parbat, Reinhold was badly frostbitten, losing six toes. It made him less comfortable climbing rock – so he turned his attention to the icy Himalayan behemoths.

8. He’s got a way with words

Messner uttered the following gems:

9. And sensational hair

This might actually be the key reason we love him. Messner has more hair at 74 that most people have at 24 – and a proper beard.

That's a haircut Credit: ALAMY

10. He is fast

His 10-hour ascent of the Eiger’s North Face was unheard of at the time. The record, for a roped party, stood for 34 years.

“Climbing is always dangerous,” he told Telegraph Travel back in 2008. “It’s chaos up there, stones are falling down, lightning may be coming and you have to survive. The art of climbing is the art of survival. The best climber is the man or woman going in the most crazy places but surviving.”

Messner flew up the Eiger (not literally)

11. And doesn’t give up easily

He reached the summits of Cho Oyu, Dhaulagiri and Makalu despite at least one previous failed attempt.

12. He’s now dedicated to saving the environment

He was one of the founders of Mountain Wilderness, which aims to preserve lofty regions around the world. Respectful mountaineering and sustainability is good; heli-skiing, overdevelopment and snowmobiling is bad. (He abandoned a 1996 attempt on Gasherbrum II because its base camp was overrun with climbers).

13. He helped create some of the most beautiful buildings in Europe

In recent years Reinhold set up the Messner Mountain Museums, which document the culture and history of high-altitude areas. They are in six South Tyrol locations and are all pretty stunning (not a suprise considering Messner has a degree in architectural engineering).

A photo posted by Tiberio Sorvillo (@tiberio_sorvillo) on Oct 11, 2016 at 4:46am PDT

One of the five Messner museums Credit: ALAMY

14. And was even a eco-politician

Reinhold held office as an MEP for the Italian Green Party from 1999 to 2004.

15. He teamed up with Werner Herzog

Though he has written 20-odd books on mountaineering, Messner is known as a bit of a recluse. So when he did appear in a film, in 1984, it had to be directed by someone equally awesome. Step forward, Werner Herzog.

16. He crossed Antarctica on skis

In 1986 he climbed Mount Vinson on Antarctica, thus becoming the first person to top all the Seven Summits without the use of supplemental oxygen. Three years later he returned to ski across the white continent (well, why not?). He and German explorer Arved Fuchs were the first to cross Antartica without any assistance.

17. And the Gobi desert (not on skis)

This 2,000-km journey was made as recently as 2004. He also walked across Greenland in 1993 (a 2,220-km trek).

The Gobi desert: easier to tackle in a car Credit: AFP or licensors/PATRICK BAZ

18. He lives with yaks in a castle

The great man now spends much of his time tending to a herd of yaks in the 13th-century castle he calls home.

Give him a castle, a walking staff, and a herd of yak, and he'll be happy Credit: ALAMY

19. He's a little bit odd

Messner claims to have seen a yeti-like creature in Tibet in 1986 - and spent 12 years researching a book (My Quest for the Yeti: Confronting the Himalayas' Deepest Myth) on the subject.

Don't joke about yetis Credit: Rex Features

20. But he just wants to chill

Messner is notoriously grumpy, aloof and holds grudges (he didn't speak to his old partner Peter Habeler for decades) - but all he really wants is peace and quiet. And we can all relate to that.

"Maybe [my final chapter] is to live in a cave somewhere and forget about everything, like my hero and favorite philosopher, Milarepa, the Tibetan thinker who always lived in a cave," he told Outside Magazine in 2002. "I will again be my own ruler, like when I was a child."