For the small airplane freaks out there ---
Fly low above a flat deck of stratus with a good sun above you --
The shadow of your airplane will be surrounded by a full 360 degree rainbow -- truly beautiful -- heading into the wind and practicing your slow flight can prolong the view, but my attempt at photography failed miserably -- any advice from experts? It's VERY bright and some filters or some such might do it.
Oh yes, in controlled airspace you're in violation of the 1,000 ft.above regulation.

-- the folkie flight instructor --