Australia, China and the US have collaborated on a mission to medically evacuate an Australian expeditioner from Antarctica.
The operation took five days, used ships, helicopters and planes, and canvassed thousands of kilometres of the icy continent.
Australian Antarctic Division Director Kim Ellis described it as one of the most complex and challenging medical evacuations his team has undertaken in recent years.
The unwell Australian was at Davis research station in east Antarctica when the operation began.
By chance, a Chinese icebreaker was travelling to a nearby Chinese research station.
Its helicopters were sent to Casey to transport a number of Australians from Davis to a site 40km inland to build a ski-way so a US aircraft could land.
In the meantime, a US ski-equipped Basler aircraft was being prepared.
It flew 2,200km from McMurdo research station to Australia's Wilkins Aerodrome, near Casey station, to pick up an Australian doctor.
The plane then flew to the skifield near Davis to pick up the patient and return to Wilkins Aerodrome.
The journey between Wilkins and Davis was a 2,800km round trip.
An Australian Airbus A319 passenger aircraft was ready at Wilkins to pick up the patient, who was flown to Hobart on December 24.
Australia does not have ski-equipped, intra-continental aircraft in Antarctica at the moment.
In a video statement, Mr Ellis said the operation involved a "massive level of multinational cooperation" and "really reflects the very best of that multinational activity that happens in Antarctica".
He singled out the Australian expeditioners for praise citing their "courage, resilience and skill in deploying to these remote airways and ski fields" to allow the evacuation to occur.
The patient's illness is not related COVID-19. Further details of their condition have not been revealed.
The team was lucky to have good weather during the five-day operation.