Midnight sun
Midnight sun is a phenomenon that exists north of the Arctic Circle and south of the Antarctic Circle, where the Sun won't set at all and remains above the horizon at solar midnight. It means that the sun, on parts of the year, is visible the whole night long. The sun above the horizon at midnight in the Arctic or Antarctic summer.
There are no people living permanently south of the Antarctic Circle (like Antarctica), but in Alaska, Canada, Norway, Greenland, Sweden, Finland, Russia, and some other countries north of the Arctic Circle, it is possible to watch the Midnight sun in the summer.
The opposite of the Midnight sun is the Polar night, where the Sun won't rise at all and remains below the horizon even at solar noon.