If your ever in Charleston South Carolina do yourself a favor and as you travel around the city, look at the porch (top and bottom) and you will see a pattern quickly emerging. Predominately the underside of the porch ceilings are painted a light blue reminiscent of the sky on a clear summers morning, BUT WHY???
Charleston was influenced greatly by the Gullah culture brought to the city through the slavery trade. In Gullah culture there is a superstition/belief that at under the dark cloak of night when man is most vulnerable as he sleeps vile and villainous spirits (christian minded people would call them demons, while others might see the spirits as ghosts) lurk luridly looking for human victims. Now the Gullah people devised a extremely simple and effective approach to warding off these nightly terrors, they just painted the undersides of all porches of the house with light sky blue paint.
The reason was a simple as the remedy, see with the porch ceilings being sky blue any evil entity who set foot on said porch would look up and see the sky blue paint. The paint was intended to fool the malevolent monsters into thinking it was day time and thusly they couldn’t harm the occupants of the house as during the day the spiteful spirits must remain trapped in the after life.