A US Air Force plane has rescued three sick workers from a South Pole research station.
The C-141 transporter jet flew out to the base from the US state of California via New Zealand on Friday.
It left the McMurdo Station, on Ross Island, on Saturday with the workers on board and flew them to the New Zealand city of Christchurch.
McMurdo Station is normally closed from late February until October because of freezing weather.
Workers at the base had prepared a special runway, called Pegasus, for the plane, according to the US National Science Foundation (NSF), which runs the base.
The evacuation flight was carrying workers to replace the patients.
The plane completed its mission in clear conditions, landing at McMurdo in temperatures of -25 degrees Celsius (-13 Fahrenheit).
The NSF had also asked the Royal New Zealand Air Force to keep a C-130 turboprop aircraft on standby in Christchurch for possible use in emergencies throughout the medical mission.
A doctor, assistant and physical therapist serve about 200 people stationed at the McMurdo base, the largest Antarctic station.
The station also has a "telemedicine link", which enables medical personnel at the station to consult US experts about medical diagnoses and treatments.
However, the NSF said that after an assessment of the patients' conditions it decided the workers should continue their treatment at a more advanced facility.
In September 2003 a sick worker was rescued from the Amundsen-Scott South Pole Station, the third such medical rescue from the South Pole in four years.