Penguin sketches made by Captain Scott and Ernest Shackleton have been found in a basement at Cambridge University.
The legendary explorers drew the pictures on blackboards, probably for public lectures, in 1904 and 1909.
Nobody knows how the fragile images, in need of cleaning and restoration, ended up at the University's Scott Polar Research Institute.
Staff are appealing for donations to help preserve the signed chalk drawings and put them on public display.
Chalk and charm
"People often compare Scott and Shackleton in terms of their achievements as explorers and their leadership qualities," said Dr Huw Lewis-Jones, the historian and curator of art who found the images.
"Now, albeit with a smile on our faces, we can judge their artistic abilities as well."
He said they were still trying to trace how the pictures arrived at the institute but he was sure they were authentic.
"Some people may think they look a little crude but I think they are incredibly charming," he added.
"They were drawn at public lectures in front of an enthusiastic audience, to laughter and to cheers, and then signed with a flourish.
"It's like having the explorers' autographs, only more wonderful, because each has signed their name next to a hand-drawn penguin."
Saved from obscurity
Scott made his drawing in 1904, after returning from his voyage aboard the Discovery.
Shackleton, who also took part in the Discovery expedition, made his sketch five years later, after coming within 150km (90 miles) of the South Pole - the furthest south any group had been at the time.
"Because they are so special we want to make sure that they are preserved for the future," said Heather Lane, librarian and keeper at the Scott Polar Research Institute.
"We've managed to save these penguins from obscurity in the basement. Now we want to get them cleaned and restored so that visitors can enjoy them."