Cloud-cuckoo-land \KLOUD-koo-koo-land\ noun
1. An idealized, unrealistic state; a place out of touch with reality; an imaginary place where silly or unrealistic people metaphorically reside.
Origin: From Greek Nephelokokkugia- nepele 'cloud' + kokkux 'cuckoo'. The word was coined in 'The Birds', a comedy by Athenian playwright Aristophanes. Nephelokokkugia was the name of a city in the sky, built by the birds in collaboration with some Athenians.