A spectacular display of nacreous clouds © Atmospheric Optics is sometimes seen over the polar regions, especially in the winter months. These clouds occur in the stratosphere at a height of 15-25 kms high in the atmosphere, and pick up their pastel colours due to extreme low temperatures of around -175°F. Due to their appearance they are called "Mother of Pearl Clouds" and occur mostly (though not exclusively) in the polar regions.
Such sights are unforgettable, and one should have time and the eye to sit and admire the many miracles of nature. In nature, every moment is a miracle, wherever you may be.