Shackleton & party celebrated Midwinter's Day in 1915 on Endurance (the ship sank 5 months later crushed by sea ice in the Weddell Sea). Most of the people in this photo would spend a miserable Midwinter’s Day in 1916 (alive nevertheless!) huddled in stone huts on Elephant Island

On the same day in 1911, 600km away, Scott and his party celebrated Midwinter's Day at the Cape Evans Hut on Ross Island #Antarctica. The following year, five would perish on the return journey from the Pole; pic @scottpolar #Solstice #ShortestDay

Here’s Amundsen (4th from right) and his party celebrating Midwinter's Day in 1911 at their Framheim base, Bay of Whales #Antarctica. Six months later, five of them were standing at the South Pole @FramMuseum @NorskPolar #Solstice #ShortestDay

Solstice! Happy midwinter’s day to everyone in #Antarctica! The Sun is over the Tropic of Cancer; the greatest geographical extent of the southern polar night has been reached, radiating out from the South Pole, 90°South, as far as the Antarctic Circle, 66°33′South #Solstice

Today is #WorldAlbatrossDay! Here’s the Southern Royal Albatross, largest seabird with 3m wingspan. It breeds on NZ's sub-antarctic islands, dispersing over the Southern Ocean. They stay aloft for long periods using dynamic soaring, flying 190,000km a year! pic @TennysonAlan

Lost in the Arctic: on a rescue mission in search of crashed airship Italia. #OnThisDay #OTD in 1928, Roald Amundsen disappeared near Tromso, Norway, flying with five others; his body never found. First to the South Pole in 1911 - he was one of the greatest explorers of all time

8 ice ages over 740,000 years, the 3.2km EPICA ice core from Dome C #Antarctica, 1st data published #OnThisDay in 2004. The longest undisturbed chronicle of environmental change, extending our knowledge 300k years beyond the Vostok ice core https://t.co/aMv5Bho0mm pic @BAS_News

What colour should the new Scott Base be? Green, Blue or Orange? @AntarcticaNZ wants you to vote! The new scientific research station on Ross Is will be powered by 97% renewable energy. Vote here https://t.co/xGPXtL3KrC #Antarctica #ColourScottBase #ScottBaseRedevelopment

Approaching the Lemaire Channel in the polar twilight, on the western coast of the Antarctic Peninsula, icebreaker Nathaniel B Palmer heads south towards Marguerite Bay on a research voyage to study krill, plankton & crabeater seals @NSF #Antarctica #MarineZoology pic Alex Brett

Time-lapse sequence captures the progression of last week’s lunar eclipse at the South Pole, with aurora australis and galactic center as backdrop. At right, the South Pole and BICEP Telescopes @NSF; pic Aman Chokshi

Happy World Penguin Day! Know your penguins! There are 18 species, all found in the Southern Hemisphere, though the Galapagos lives on the Equator. Six are native to #Antarctica; many are threatened or endangered #WorldPenguinDay #penguins pic Peppermint Narwhal

As the weather clears at @NSF McMurdo Station on Ross Island #Antarctica, curtains of aurora australis make their first dramatic appearance of the season; pic Danny Hampton

“Had we lived, I should have had a tale to tell of the hardihood, endurance, and courage of my companions which would have stirred the heart of every Englishman. These rough notes and our dead bodies must tell the tale” - Robert Falcon Scott, last diary entry #OnThisDay in 1912

#Equinox! The Sun is crossing the celestial equator heading North; the one and only sunset of the year at the South Pole is currently underway, bringing an end to six months of 24/7 sunlight at 90°South #SouthPole #Antarctica

"I am just going outside and may be some time" #OnThisDay #OTD in 1912 Captain Lawrence Oates walked to his death on the Ross Ice Shelf, believing he was slowing the others down; photo by Herbert Ponting

Happy #StPatricksDay! Here’s Tom Crean, Irishman of #Antarctica: veteran of 3 Antarctic expeditions; 1. one of the last to see Scott alive; 2. saved lives of Lashly & Edward Evans! 3. sailed in James Caird! 4. traversed South Georgia with Shackleton & Worsley in search of rescue!

Late sun dogs at the South Pole low in the sky, possibly the last of the season before the equinox sunset next week and the commencement of the long polar night at 90°South. This view from @SPTelescope, with @BICEP_Keck at right @NSF #SouthPole #Antarctica pic @aman_chokshi

The annual minimum sea ice extent around #Antarctica occurred on 25 Feb - and it was a record minimum: for the first time since satellite records began in 1979, the min extent fell below 2 million km2, reaching a minimum of 1.92 million km2 (741,000 square miles); pic @NSIDC

Finally free after a year trapped in sea ice, #OnThisDay in 1899 the first scientists to winter-over in #Antarctica used dynamite to clear steamship Belgica, barely escaping a 2nd winter! Led by Adrien de Gerlache, also onboard: Roald Amundsen, Henryk Arctowski & Frederick Cook

Found! The wreck of Shackleton’s Endurance has been discovered 3008m below the surface of the Weddell Sea; last seen when it was crushed by ice in Nov 1915. With no wood-eating micro-organisms on the Antarctic seabed, the shipwreck is well preserved; pic @Endurance_22 #Endurance