Explorers' descendants follow in their footsteps
The adventurers made it to the point where Shackleton was forced to turn back on 9 January, 1909, only 97 miles from the Pole, defeated by blizzard conditions and dwindling rations.
The 2009 team hopes to achieve what their forefathers could not, and finish the 900-mile journey to the Pole.
The emotional trip is only the latest in an increasing number of expeditions to Antarctica, especially by Britons.
Henry Worsley, leader of the expedition, said they were looking forward to completing "unfinished family business" by reaching the Pole.
He said: "The past 57 days have been phenomenally challenging and physically shattering. But to stand at Shackleton's 'Furthest South' exactly 100 years later and mark his extraordinary feat of endurance and leadership has motivated all of us. It's onwards to the Pole now."
Mr Worsley, 47, an army officer from Hereford, is a descendant of Shackleton's skipper, Frank Worsley.
His fellow explorers are Will Gow, 35, a City worker from Ashford in Kent, who is related to Shackleton by marriage, and Henry Adams, 33, a shipping lawyer from Snape in Suffolk, a great-grandson of Jameson Boyd-Adams, Shackleton's number two on the unsuccessful expedition.
To reach the historic point, the trio have had to walk 800 miles across Antarctica, hauling sledges weighing 300lb for up to ten hours a day in temperatures dropping as low as -52C. Biting headwinds can reach speeds of 150mph, turning their breath to ice and freezing the sweat on their bodies.
They had hoped to be joined by another three expedition members today for the final push on the Pole, but the second team was delayed by bad weather.
Last month, the trio celebrated Christmas Day as their forebears did 100 years before: with cigars and a spoonful of crme de menthe.
The other adventurers on the trip are: student Tim Fright, 24, from Billingshurst, West Sussex, a great-great-nephew of Frank Wild, the only explorer to accompany Shackleton on all his missions; David Cornell, 38, from Andover, Hampshire, a City fund manager and another great-grandson of Boyd-Adams; and Andrew Ledger, 23, a policy researcher from Dronfield, near Sheffield, who won his place on the expedition as part of an open competition.
The combined team of six expect to reach the South Pole around 20 January.
Shackleton set out on the first of his Antarctic expeditions with the ship Nimrod in 1907. In October 1908, having spent the southern winter at their base on the continent, the explorer and his team set out to reach the South Pole.
But they were forced to turn back at the 97-mile mark in the face of almost certain death.
Although Shackleton failed, he travelled further south than anyone else had before, and was hailed a hero and knighted when he returned to the UK.
Norwegian explorer Roald Amundsen and his team became the first people to reach the South Pole in December 1911.
The Matrix Shackleton Centenary Expedition is also being used to launch a 10 million Shackleton Foundation, which will fund projects that embody the explorer's spirit and hunger for "calculated risk".
The spirit of Shackleton has influenced an increasing number of people to travel to the inhospitable region, with the number of visitors quadrupling since the turn of the decade.
The idea of Antarctica as a destination for physical pursuits or tourism took root in the late 1960s, when only a few hundred took to the ice each year.
That number increased gradually over the years until in 2000, there were just over 12,000 visitors to Antarctica. Since then the figure has soared, with more than 46,000 visiting last year, according to the International Association of Antarctica Tour Operators.
British nationals form a significant proportion, with 7,300 visiting last year compared with 1,200 nine years ago.
That is more than the estimated 5,000 people who trek to the Mount Everest base camp every year.
ERNEST Shackleton was born in Co Kildare in 1874 and his family moved to London in the 1880s.
He defied his father's wish that he become a doctor, and joined the merchant navy, later qualifying as a master mariner.
In 1901, he was chosen to be part of an Antarctic expedition led by Robert Falcon Scott, but fell ill and had to turn for home. He led his own expedition to the Antarctic on Nimrod, leaving New Zealand for the continent early in 1908, and making several scientific discoveries.
In 1914, he made his third trip, on Endurance; despite extreme hardships after the ship sank, none of his men died.
Shackleton's fourth trip aimed to circumnavigate Antarctica, but on 5 January, 1922, he died of a heart attack off South Georgia. He was buried on the island.