It’s not just height that makes a mountain mean. Different routes can make one side of a mountain a cinch and the other side nearly impossible. The weather can turn a technically easy climb into a deadly expedition. Whatever the weather, many aspire to tackle the world's hardest mountains to climb. Here's our ranking of the 11 trickiest ascents. Glorious and gruelling, gorgeous and grim – these peaks are as dangerous as they are awe-inspiring.

1. Annapurna, Nepal

Average time to summit: 40–50 days

By no means should a mountain’s height be confused with its technical difficulty. Annapurna, in Nepal, the tenth highest peak in the world, is deadly proof. With a near 40% summit fatality rate, a mountaineer is more likely to die here than on any other 8,000m climb.

The threat of storms and avalanches loom over the mountain’s hulking glacial architecture. The south face, in particular, is widely considered the most dangerous climb on Earth.

Thanks to Helicopter Tours, the Annapurna range can now also be explored from the Base Camp without the strenuous trek.

2. K2, China and Pakistan

Average time to summit: 60 days

Though plenty of peaks in the Himalaya could contest for second on our list, K2’s technical difficulty is legendary. It’s also the second tallest mountain in the world. No list of the hardest mountains to climb would be complete without it.

In an infamous section called the “Bottleneck”, climbers traverse a towering overhang of precarious glacial ice and massive, sometimes unstable, seracs. It’s the fastest route to the top, minimizing time climbing above K2’s “death zone”: the 8,000m altitude above which human life can only briefly be sustained. But too often these seracs come tumbling down, taking climbers with them.

3. Kangchenjunga, India and Nepal

Average time to summit: 40–60 days

While climbing death rates are generally decreasing, Kangchenjunga stands as an unfortunate exception to the rule, taking more lives as time goes on. It seems fitting that the mountain is regarded as the home of a rakshasa (or man-eating demon). Only 187 have ever reached the top, though out of respect for the mountain’s immense religious significance among the region’s Buddhists, climbers have always stopped short of the summit.

4. Baintha Brakk, Pakistan

Average time to summit: undetermined

Commonly called “The Ogre”, towering Baintha Brakk has only been summited a handful of times. Immense in scale, intricate in shape and harrowing in incline, this mountain is both the blight and biggest desire of mountaineering’s most hardcore enthusiasts. From the start, any attempt at this mountain is a veritable struggle for survival.

5. Mount Everest, Nepal and Tibet

Average time to summit: 54 days

Surprised to see the world’s tallest mountain in the middle of our list? Make no mistake, Everest is still a difficult climb. Weather and altitudes can be deadly, and avalanches have claimed dozens of lives in recent years.

Everest's glory has faded somewhat with the mountain’s commercialisation. While once it was a feat not many travellers could claim to have achieved, today’s services enable climbers to hire local sherpas to lug their packs, employ chefs to prepare food, and even have a personal medic at Base Camp in case of injury.

What's more, the crowds that Everest attracts have become an unfortunate danger in themselves. If you do invest in a climb, prepare to join a traffic-jam-like queue of hundreds of climbers waiting their turn to reach the summit.

Planning to trek the Mount Everest? Get in touch with our local experts in Nepal and modify your trip, for example the Exclusive Everest itinerary.

6. Denali, Alaska, USA

Average time to summit: 21 days

The altitude, awful weather, relative isolation and punishing temperatures all pose a serious threat to those who attempt to summit North America’s tallest mountain, previously known as Mount McKinley. Further, its high degree of latitude means that atmosphere and oxygen are spread very thin.

Despite having only a 50% summit success rate, Mount Denali in Alaska never fails to tempt climbers. Perhaps the words of one of the first climbers to the summit, Robert Tatum, can explain its allure: “The view from the top of Mount McKinley is like looking out the windows of Heaven”.

7. The Eiger, Switzerland

Average time to summit: 2–3 days

The difficulty of the Eiger’s north face has earned it a disturbing nickname: Murder Wall. Attempting the summit requires serious technical skills and ice axe finesse. The sharp overhang, 1,800m face and ever-increasing threat of falling ice and rock (a result of global warming) have killed at least 64 climbers since first successful ascent in 1938.

Prefer to admire the mountains from a different point of view? Consider a Skydive from a Helicopter in Interlaken to get a new outlook on the Eiger.

8. Cerro Torre, Argentina and Chile

Average time to summit: 4–7 days

Cerro Torre has long captivated the hopes and hearts of climbers, a jagged spire jutting out of the Patagonian Ice Field’s mountains.

Notoriously sheer with a peak guarded by a hazardous layer of rime ice formed by battering winds, it does not offer itself up easily. Climbers must be prepared to tunnel through the ice and deal with vertical and overhanging sections.

Interested in exploring more of Argentina and Chile? Our local experts would be happy to help, get in touch here.

9. Matterhorn, Switzerland

Average time to summit: 5 days

An icon of the Alps, the wizard's-hat peak of the Matterhorn is successfully tackled by hundreds of climbers every year. However, this is no reason to assume it an easy climb.

The mountain has claimed more than 500 lives since 1865 and takes a few more each year. Falling rocks have always posed a threat, but the crowds scrambling towards the peak every day during the Swiss summer have created new challenges for climbers to conquer, and new reasons to try the more demanding conditions of winter.

If you prefer to take an easier route, consider taking the Gornergrat Bahn from Zermatt for spectacular views of the Swiss Alps.

10. Vinson Massif, Antarctica

Average time to summit: 7–21 days

Fabled Vinson was first glimpsed by human eyes in 1958. Since then, some 1,400 people have reached the summit. Weather poses the greatest threat here: it has some of the coldest temperatures on the planet and winds that can easily surpass 80 kilometres per hour.

The simple fact that it could take weeks to get to a proper hospital in an emergency makes this a remarkably dangerous excursion. Furthermore, getting to Antarctica is going to cost you – a lot.

11. Mont Blanc, Italy and France

Average time to summit: 2 days

OK, it may not be that tall compared to peaks in the Himalayas, and typical routes aren’t that technically challenging. But Mont Blanc is still a challenging climb. The mountain's position on the border of Italy and France makes it all the more convenient.

This sort of heady logic brings many tourists to Mont Blanc every year, and maybe that’s why Mont Blanc has killed more people than any other mountain. Some 8,000 have perished on this scenic European climb, most of them novices. Be responsible and be prepared if you’re planning to climb Mont Blanc, its power shouldn’t be taken lightly.

If you're based in Geneva and only have a day, we recommend taking a day tour to Chamonix, from where one can take the cable car to Mont-Blanc.

Top image: Matterhorn mountain © Farbregas Hareluya/Shutterstock