For us mortals, the conquest of Everest seems to be the ultimate achievement. But for mountaineers, conquering the highest peak is just the beginning of a brave, new world. Starting from Everest, it spreads out to all the over-8, 000 m peaks, then to the highest points of the seven continents, and finally to the North and South poles.

"Climbing mountains is partly inspired by reaching the summit and there is only one highest point on our planet, so Everest will always inspire climbers, " says Danish mountaineer and climbing guide Harry Kikstra, who has climbed the highest mountains of all continents. Perhaps that makes Mount Everest the eight-thousander with the maximum number of ascents.

Eight-thousanders — a mountaineering slang — is the collective name for the 14 highest mountain peaks of the world, all more than 8, 000 m high. Incidentally, all of them are either in the Himalayas or the Karakorum range.

Everest might be the highest, but it's not the toughest. Climbing K2, the second-highest peak on earth, is far more difficult and a successful summit climb is often compared to an Olympic gold in mountaineering. "There are no safe routes, all are prone to avalanches. Furthermore, K2 is steeper, and needs more technical expertise than Everest, even on the easiest routes, " says Kikstra.

The peak was known for carrying a curse on women climbers — the first five women making it to the top died either during descent or on some other summit. The curse was broken by Spaniard Edurne Pasaban in 2004, who climbed Annapurna last week, becoming the second woman after Korean Oh Eun-Sun to climb 13 eight-thousanders.

Some, however, say that the difficulty faced in climbing a peak can only be indicated by the number of mountaineers that perish while attempting to conquer it. By this measure, Annapurna beats even K2, taking nearly one life for every two successful summits. Spaniard Inaki Ochoa de Olza, who had climbed 12 eight-thousanders without oxygen, and Kazakh Anatoli Boukreev, who had made 18 ascents to the eight-thousanders, were both killed while climbing Annapurna. Similarly, Nanga Parbat, Manaslu and Kanchenjunga are dangerous peaks, killing nearly one person for every five successful climbs. Italian Reinhold Messner, considered one of the greatest mountaineer of all times, lost his brother on Nanga Parbat in 1970. Six of Messner's toes had to be amputated because of frostbite.

But conquering the highest and deadliest of mountains has never stopped climbers from doing what they feel they were born to. For them, meeting one challenge just marks the beginning of another one. US businessman and mountaineer Richard Bass took the initiative to create one of the most famous challenges of mountaineering — climbing the highest mountains of each continent — Everest (Asia), Aconcagua (South America), McKinley (North America), Kilimanjaro (Africa), Elbrus (Europe), Vinson Massif (Antarctica) and Kosciusko (Australia). After climbing Everest on April 30, 1985, Bass became the first person to climb the seven summits. Messner revised Bass's list by replacing Kosciusko with Carstensz Pyramid in Papua, Indonesia, as the highest peak in Oceania. Canadian photographer and mountaineer Pat Morrow became the first mountaineer to meet the challenge after he climbed Carstensz Pyramid on May 7, 1986. This was shortly followed by Messner himself who climbed Vinson Massif on December 3, 1986.

Messner, in fact, came second in his self-proposed challenge because at that time he was busy climbing the eight-thousanders. He became the first person to do so on October 16, 1986. In any case, compared to the Seven Summits, climbing all the eight-thousanders is far more difficult. Only 18 mountaineers have so far succeeded in climbing all 14. The Seven Summits have been climbed by 199 people (if Kosciusko is included) or 178 (if Carstenz is counted). So much so that 105 persons have done both, including Malli Mastan Babu from India. In 2006, Malli set a world record as the fastest climber to finish the Kosciusko list in 172 days. The record was broken in 2008 by Danish climber Henrik Kristiansen, who completed the list in 136 days.

The story doesn't end even here. For those who have climbed to the top of the world, the new challenge is to reach the ends. In 1998, British explorer David Adams became the first person to achieve the Explorer's Grand Slam by climbing the Seven Summits and also reaching the North and South Pole. So far, 13 others have achieved this feat. In 2005, Korea's Park Young-Seok became the first person to complete the true Adventure Grand Slam — Seven Summits, eight-thousanders and the poles.

What next? Climbing the second highest summits of each continent? This may seem easy but it's more than an extension of the first list — in most of the continents the second highest summit is far more difficult to climb. Perhaps, similar lists of seven second summiteers will soon become common as irrespective of the difficulty these peaks pose man will continue to scale one more peak. To quote George Mallory again: "Because it's there. "