In some areas of the Earth during the summer, the Sun remains visible for over 24 hours or even months without getting dark. This phenomenon is called the 'Midnight Sun' and is observed at latitudes above the Arctic Circle and below the Antarctic Circle. The phenomenon is due to the inclination of the vertical axis of the Earth by 23 ° 26΄ in relation to its plane of rotation around the Sun.. Its duration depends on the latitude, from which we observe it. The closer the observer is to the north or south pole, the longer it lasts. For example, the sun shines continuously for 6 months on the poles, while in the northern tip of Finland it is limited to 73 days. The opposite phenomenon, where the night lasts for more than 24 hours during the winter, called 'Polar Night'.