The explorers have already walked 800 miles across Antarctica
Three descendants of Sir Ernest Shackleton and his team have reached the point their ancestors abandoned an attempt to reach the South Pole.
Lt Col Henry Worsley, from Hereford, Will Gow, from Kent, and Henry Adams, from Suffolk, are trying to complete Shackleton's failed expedition.
They have made it to the point 97 miles (156km) from the pole, where he was forced to turn back on 9 January 1909.
The men are 57 days into their 80-day Matrix Shackleton Centenary Expedition.
So far they have walked 800 miles across Antarctica, hauling 300lb (136kg) sledges for up to 10 hours a day in temperatures that have dropped as low as -52C.
Lt Col Worsley, 47, is the expedition leader and a descendant of Shackleton's skipper Frank Worsley.
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."
Shackleton set out on his Nimrod expedition in October 1908, hoping to become the first person to reach the South Pole.
But icy blizzards and dwindling rations forced him to turn back 97 miles from his goal on 9 January 1909.
The trio celebrated Christmas Day as their forebears did 100 years before, with cigars and a spoonful of creme de menthe.
Mr Gow, 35, a City worker, from Ashford, is related to Shackleton by marriage.
Mr Adams, 33, a shipping lawyer from Snape, near Woodbridge, is a great-grandson of Jameson Boyd-Adams, Shackleton's number two on the unsuccessful expedition.
Andrew Ledger, 23, from Derbyshire, Tim Fright, 24, from West Sussex and David Cornell, 38, from Hampshire, were due to meet the trio at the 97-mile point on Friday but have been delayed by bad weather.
The expedition is being used to launch a £10m Shackleton Foundation, which will fund projects that capture the "explorer's spirit" and hunger for "calculated risk".