Half of Norway to the north is within the Arctic Circle (above 66.55 degrees north), where for six months sun never sets (remains above the horizon) and the rest of six months it remains below the horizon, never rising, hovering around in a slanted circle. During the six months day time, irrespective of our 24hours body rhythm sun remains even when it is midnight as per our watches. This gives it the name "land os midnight sun".
Just outside the Arctic circle (below 66.55 deg N), the sun's hovering circle cuts the horizon to the south and the sun actually dips (sets and rises after a while) below for a while at midnight. As we go further south this dip occupies more of below horizon and for more time. The circle of sun's path lifts up to become more vertical.
In winter the reverse happens within the Arctic Circle. The circle of sun's path drops down to horizon, then gradually it goes below the horizon totally never rising for six months.
It is observed in northern parts of Sweden, Finland, Russia, Canada, Alaska (USA) and Greenland (except the southern tip) and Arctic islands.