This phenomenon is known as a mirage. A common type of mirage can be seen on hot days when road surfaces absorb a great deal of incoming solar radiation. The air just above the road is relatively cooler and when the light is refracted into our eyes, the pavement appears wet. When warm air rests over a cold surface, the Badlands are visible in Rapid City. This phenomenon is known as Fata Morgana, is a type of superior mirage.
Superior mirages appear right side up and inferior mirages are upside down.
So now you not only know why the sky is blue, but why some of these stunning visual phenomenon occur.