Cool video from the ever awesome Sixty Symbols that shows the green flash.
.Rainbows and Sun’s Green Flash
By Gaylord Johnson
FEW people realize that the famous green flash as well as the marvelous color effect called the rainbow, is explained by a principle which can be demonstrated indoors with the simplest of laboratory materials. In fact, not many persons have seen the green flash at all, either at sunset or sunrise, although it occurs frequently at sea or on land when the sun rises or sets in a clear sky on a level distant horizon.