When people accuse you of building castles in the air, they are not usually congratulating you on an incredible engineering feat, but more likely trying to bring you back down to earth with a thud. Synonymous with daydreams, pipe dreams, and all other dreams unlikely to come to fruition, castles in the air are at best a hopeful vision, and at worst, a hopeless illusion.Although the phrase “castles in the air” the original phrase was “castles in Spain” is most often used to describe imaginary constructions, it can also be used to describe a very real optical phenomenon—the fata morgana effect—in which different levels of hot and cold air distort the appearance of objects on the horizon to make them look like, well, castles in the air.

read more The Fata Morgana Effect: Interesting Thing of the Day.