This was
your sky.

Nacreous Clouds over Sweden

These vivid nacreous clouds, also known as mother-of-pearl clouds, were observed over Tanndalen, Sweden. They are a type of polar stratospheric cloud that forms when unusually cold temperatures in the lower stratosphere create ice crystals. These clouds are still sunlit at high altitudes, causing them to diffract light and display iridescent colors. They are a rare sight, especially at high latitudes during winter.