Mother-of-pearl clouds as seen from Kuopio, Finland, early in the year 1987. This photo was taken about half an hour after sunset, and it's getting rather dark. These mother-of-pearl clouds were unusually colorless, looking more like noctilucent or cirrus clouds. In some parts of the cloud and in the beginning of the display the colours were more distinct, but unfortunately I wasn't in the same place with my camera at that time. I have photos of more colorful mother-of-pearl clouds, but they are not as beautiful as this one.

(© Timo Nousiainen)