The postcard-pretty, snowcapped mountain looming over the Swiss mountaineering and ski resort village of Zermatt does not look like a killer.
The giant pyramid of rock will be the subject of celebration this week, ablaze with a string of 50 lamps marking route taken by the first alpinists to reach the summit on July 14, 1865.
But the jubilation of the expedition's leader, British mountaineer Edward Whymper, was short-lived when on the descent, four of his party fell to their deaths.
Each year between July and September, when weather conditions permit, each day up to 200 mountaineers, including many New Zealanders, attempt to climb the mighty slab of mountain that has claimed twice as many lives as Mt Everest.
Christchurch technician Andy Leslie began the greatest climb of his life one late-summer morning in -September 2013.
The 4478m Matterhorn represented the 30-year-old's greatest challenge - he had just three years' of rock and mountain climbing experience.
Aware of the mountain's death toll, Leslie was relying on rigorous training and preparation to pull him through. "I wanted the ultimate experience and to climb a mountain people would recognise," he says. "Everything in my life was lined up.
"I was feeling confident about my rock climbing, I had some time off work, a bit of money, so decided to give it a go."
Knowing the fatalities on the Matterhorn were heavily skewed to those climbing without a guide, Leslie sought the expertise of Wanaka's ¬Adventure Consultants to help ¬organise a guided climb.
In preparation, he spent three days getting to know his Dutch guide, ¬Roeland van Oss, and climbing peaks higher than 4000m with him.
"You have to be able to trust each other with your lives," says Leslie.
The day before the ascent, the pair spent the night at Hornli hut, 3260m above sea level, the starting point for most climbs to the summit. Up at 3am, they had breakfast then joined the queue to begin the ascent.
"The pecking order was very clear," says Leslie. "Climbers with a mountain guide were at the front of the queue. Those scaling the peak unguided were at the back."
This format is for safety reasons as any climber straying from the route becomes a hazard for those below by dislodging rocks.
The guard in charge of the hut staggers climbers' departures to reduce congestion on the knife-edged Hornli ridge, where in parts there is space only for one person at a time.
The procession of mountaineers winding up the ridge is impressive, with each climber wearing a head torch. This famous "Head Lamp Parade" is visible through binoculars from Zermatt when the weather is clear.
With a climb of this magnitude there are milestones that must be met. Van Oss had stressed to Leslie they must be at Solvay hut by sunrise, otherwise they should turn back.
That represents two-thirds of the distance up the mountain, but only half the climb time, as the remaining ascent becomes more difficult.
With the first milestone met the going got tough, as they reached the fixed ropes (steel ropes bolted to the mountain face) below the summit.
Only one person can pass at a time. This creates a bottleneck and sometimes appalling behaviour, as impatience and exhaustion bring out the worst in climbers.
Leslie recalls some of the climb's tougher moments. "On the last fixed rope before the summit the altitude was affecting me badly and it was hard to breathe. People were coming down as we were going up and it's not pleasant with crampons in your face.
"Nobody speaks the same language so we needed to be aggressive and just push our way through."
Leslie reached the summit in 4½ hours and had a safe descent, stopping at the Hornli hut before continuing down the mountain to Schwarzsee Hotel in Zermatt for the night.
Although conquering this Swiss icon leaves climbers elated with success and achievement, the Matterhorn's deadly history is never far from their minds.
On July 14, 1865, a seven-member party led by British artist and climber Edward Whymper reached the summit, from where Whymper is said to have triumphantly thrown rocks down the mountain's Italian side where ¬another party had been racing the British to the top.
But returning, one of Whymper's party slipped down a precipice, dragging three others with him, an accident that was to haunt the expedition leader.
Whymper and two others would also have fallen if the rope had not snapped. On his return, one of the men was accused of cutting the rope to save their lives but an inquiry found no evidence to support the claim.
Three of the bodies were recovered but that of Lord Francis Douglas was never found. Queen Victoria, wanting to prevent any further loss of blue blood on the mountain, announced her intention to issue a general ban on Matterhorn ascents.
But the intended ban fired curiosity and British alpinists began to flock to Zermatt to make the climb. This was the start of tourism in the mountain village.
This week, the first ascent will be relived in an open-air theatre at Riffelberg, on the mountain above Zermatt, as part of the celebrations bringing the Matterhorn story to life.
To commemorate the four men who died on the first ascent, the mountain will be closed to climbers on Tuesday and one of the 50 lamps marking the inaugural route will be red, to indicate where the accident took place.
Those four will be remembered, along with others who have lost their lives on the Matterhorn, in a cere¬mony and benediction of the Grave of the Unknown Climber in Zermatt's haunting graveyard.
Despite the fixed ropes installed in the 1980s to reduce accidents, the Matterhorn continues to be the deadliest peak in the Alps and has claimed the lives of more than 500 climbers.
Anjan Truffer, head of search and rescue for the Zermatt-Matterhorn area, says the number of accidents is declining. More climbers are engaging a guide and he says there is a greater appreciation of risks on the mountain.
"Very few accidents happen with a guide."
Of the 3500 mountaineers who attempt the Matterhorn each year, 65 per cent don't make it to the summit, mainly because they climb unguided, he says.
"One of the biggest challenges for unguided climbers on the Matterhorn is finding the path. It is easy to waste time finding the right route, causing exhaustion and becoming less focused, especially on the descent, where most of the fatalities occur."
As the Matterhorn has become more popular, Truffer likens the mountain congestion to a traffic jam and says too many people, inexperienced climbers, falling rock and ¬softening snow are the main causes of accidents.
He says search and rescue ¬normally attend 20-30 call-outs a year to rescue climbers on the Matterhorn. On average, four to five climbers each season do not make it back.
To mark the 150th anniversary, the Hornli hut, where climbers spend the night before a pre-dawn departure, has been rebuilt.
Built in 1880 with 17 beds, the new hut can accommodate 130 climbers and will be opened on July 15.
Mountain that casts a shadow of death
As the 150th Matterhorn commemoration gets under way, those taken by the mountain play a bigger part in my mind.
The mountain doesn't discriminate. It has taken one of our own.
My cousin, David Heymann, was fatally injured in a fall on the Hornli ridge, leaving his brave, stoic friend, Greg Houston, to descend alone without ropes.
The Kiwi friends, both 27, studied at Canterbury University, excelling in economics and landing sought-after positions at Treasury in Wellington.
Their talent took them to London where their friendship grew, as did their passion for mountains.
With plenty of mountaineering experience under their belts, including on Mt Cook and in the Himalayas, they headed to Switzerland to climb the Matterhorn in June 1989.
On June 11, it was early in the season and the conditions were good so the pair climbed to the Hornli hut in preparation for an early morning start.
Two hours into the climb, as they traversed part of the Hornli ridge, David slipped in soft snow.
Despite trying to self-arrest with his ice axe, he just kept sliding.
He didn't stop, falling 1000m while his helpless friend looked on. To Greg, David was a speck on the Furg Glacier below.
In shock, Greg knew he needed to get off the mountain. With no ropes -David had been carrying them - he knew it would be difficult.
Greg had the protection gear and belays, some with as much as a metre of rope, so he tied them together and managed as best he could to stop himself from falling.
Down at Hornli hut he raised the alarm and soon heard a helicopter overhead. David's body was recovered that afternoon.
Still at Hornli hut some hours later, Greg was left to pack David's belongings and head down the mountain to the Swiss resort village of Zermatt.
Checking back into their hotel alone, Greg spent a harrowing few hours the following day recalling the details of their climb and the death of his friend to police via a translator.
Greg walked out with David's rucksack on his back and told me he felt "utterly isolated".
David's funeral was held in London 10 days later, followed by a memorial service in Wellington.
His ashes are scattered on Mt Cook.
- Jane Jeffries
The first ascent
British artist Edward Whymper led the first group of climbers to conquer the Matterhorn in an expedition that ended in the deaths of four of the seven mountaineers.
Whymper visits the Alps for the first time and is impressed with the unclimbed Matterhorn. Over the next five years he makes unsuccessful attempts to climb to the summit via the southwest ridge of the mountain.
Whymper decides to change his approach to the east face.
Whymper, with Swiss guide Peter Taugwalder and his two sons, Peter and Joseph, British climbers Lord Francis Douglas, Charles Hudson and Douglas Hadow and French guide Michel Croz set off from Zermatt, collecting equipment from Schwarzsee, and begin their ascent.
Joseph Taugwalder returns to Zermatt while the others continue their ascent.
Whymper and Croz reach the summit, conquering the Matterhorn.
Descent and disaster
The party begin their descent, led by Croz and followed by Hadow, Hudson, Douglas, Taugwalder snr, Whymper and Taugwalder jnr respectively, roped together in single file.
Hadow, a less experienced climber, slips and falls on to Croz who loses his footing and also falls, pulling down Hudson and Douglas. Whymper and the Taugwalders manage to keep their footing but the rope between them and the stricken climbers snaps.
Croz, Hadow, Hudson and Douglas fall to their deaths down the north face onto the Matterhorn Glacier below.
The three survivors return to Zermatt. A group of climbers report having sighted the bodies of the fallen men.
Whymper and a rescue party recover the bodies of Croz, Hadow and Hudson from the Matterhorn Glacier. Douglas' body is never found.
The world's most dangerous peaks
1. Annapurna, Himalayas
The 10th-highest mountain in the world has been conquered by more than 130 people, but 53 have died trying, making it statistically the most dangerous in the world.
2. K2, Himalayas
The world's second-highest mountain is known among climbers as one of the most technically difficult.
3. Nanga Parbat, Himalayas
The world's ninth-highest peak competes with K2 in terms of technical difficulty and has earned the nickname "The Man Eater".
4. Kangchenjunga, Himalayas
Mountain fatality rates decrease over time but Kangchenjunga, the third-highest peak in the world, is the exception. Death rates have reached as high as 22 per cent
in recent years.
5. The Eiger, Swiss Alps
Nicknamed Murder Wall, this peak is legendary among mountaineers for its danger.