Two researchers who fell ill while working at the US station at the South Pole have been evacuated safely in a small aircraft.
The National Science Foundation (NSF) said the two people - a man and a woman - arrived on Wednesday night in Punta Arenas, Chile, after travelling from the Amundsen-Scott station.
In a statement on its Facebook page, it said: "From Punta Arenas, the two patients aboard will be transported to a medical facility that can provide a level of care that is not available at Amundsen-Scott."
A medic at the hospital said the male worker had suffered a heart attack and the woman had a gastric problem.
The NSF said they were seasonal employees of Lockheed Martin, with is the prime contractor for operations and research support for the foundation's Antarctic programme.
A rescue team flew a 3,000-mile (4,800 km) round trip from Britain's Rothera station to the South Pole and back with the workers on Wednesday afternoon.
Temperatures were as low as -60C (-75F) at the South Pole and -2.5C (27.5F) at Rothera during the rescue operation.
Aircraft do not normally fly to the US polar outpost between February and October because of the danger of flying in pitch dark and cold.
Extreme cold affects the aircraft - including fuel, which needs to be warmed before take-off, batteries and hydraulics.
The station has a doctor and a physician's assistant. There have been three emergency evacuations from Amundsen-Scott since 1999.
Station doctor Jerri Nielsen, who had breast cancer and had been treating herself, was rescued in 1999.
Two other rescues in 2001 and 2003 were for gallbladder problems.
The South Pole station does astronomy, physics and environmental science research using telescopes, seismographs and instruments that monitor the atmosphere.