A hidden 9,000-strong colony of emperor penguins has received its first ever human visitors.
Scientists from the British Antarctic Survey and US colleagues discovered the colony of one metre tall penguins from satellite images.
The birds' toilet habits gave away their location, by leaving faecal stains on the ice.
Three experts from Belgium's Princess Elisabeth Antarctica polar research station have now become the first people to visit and photograph the colony.
They travelled to the site on Antarctica's Princess Ragnhild Coast in early December.
Expedition leader Alain Hubert said: "I knew from last year's satellite study that there could potentially be an emperor colony east of Derwael ice rise.
"Because we were operating not far from this the satellite location, I decided to force the way and try to access this remote and unknown place.
"The surprise was even more than all I could have expected or dreamed about: I realised while counting the penguins that this was a very populated colony.
"It was almost midnight when we succeeded in finding a way down to the ice through crevasses and approached the first of five groups of more than a thousand individuals, three-quarters of which were chicks.
"This was an unforgettable moment."
Hubert and Soete had been studying ice loss some 50 kilometres from the colony at a remote site 250 kilometres from the Princess Elisabeth research station.