As a result of earth’s axial tilt, this make the sun does not set for 6 months in the North Pole and in the Arctic circle region during the summer solstice.
Similarly, it does not set in the Antarctic circle region during the winter solstice
and at the South Pole, it also does not set for 6 months too.
Which means the sun rises and sets only once each year at the North Pole and South Pole.