Researchers at Amundsen-Scott South Pole Station have been watching the sun set for weeks. At the poles, the sun traces an excruciatingly slow corkscrew between equinoxes, first spiraling up to a point 23° above the horizon (only about as high as the sun gets in Chicago around 10am on December 21st) on the solstice, then slowly spiraling back down to the horizon over the next three months.
In about an hour from now, the last limb of the sun will slip below the south polar horizon, the twilight gradually fading for another three weeks. The sun won't appear again until September 20th.
Fourteen people will spend the next five months at Amundsen-Scott, with no possibility of leaving until the end of August.