The summer solstice (around December 21). However, below the antarctic circle, the Sun may not set for several days (depending on the exact latitude); at the South Pole, the Sun rises in September and doesn't fully set again until late March... a "day" of over 180 calendar days.
Antarctica
The longest day ever recorded occurs from September 21st to march 21st in Antarctica where scientists experience the day to last for 6 months.
The definition of equinox and solstice in Antarctica is the same as it is anywhere on earth. Notably, however, Antarctica's seasons are exactly reversed from those in the Northern Hemisphere. For example, the shortest day in Antarctica is June 21, the first day of winter, and the longest day is December, the first day of summer.
from the day a meteor hit earth til now..in Antarctica...always a snow storm
There are no 'rivers' in Antarctica, unless you consider glaciers as flowing rivers of ice. You can review the lists, below, and identify the longest glaciers in Antarctica.
Near December 21, the two continents that experience the longest day are Antarctica and Australia. In Antarctica, the sun remains above the horizon for 24 hours during the summer solstice, resulting in continuous daylight. In parts of Australia, particularly in the northern regions, the days are also long, though not as extreme as in Antarctica. However, the phenomenon of extended daylight is most pronounced in Antarctica during this time.
Lambert Glacier in Antarctica
The Antarctic Peninsula.
Antarctica has the longest coastline among all the continents.
vinson massif
The Lambert Glacier in East Antarctica, is the longest glacier in Antarctica and the world. It is about 40 km wide and about 400 km long. It drains nearly 8% of the Antarctic Ice Sheet into the Amery Ice Shelf.
You may be thinking of the Antarctic Peninsula.