Nocticulent clouds

Noctiuclent clouds (highest clouds of all) are rather rare weather phenomena, best seen only in summer between 50° and 70° north and south of the equator. They are made of ice crystals and can be seen when the sun is below horizon. I remember my grandmother in my childhood told me that "noone knows how these clouds are formed" and that some speculates they could be souls of died people... :) It brought me a mysterious feeling about these clouds which in Latvian we are calling "silvery clouds". Here you also see the white night of June - as you see the horizon is light. It's a Northern side there, Finland, North Pole where the Polar Day is going on currently. [full_width]