Xanadu is the first X word that popped into my mind.  I always associate Xanadu (the song, not the movie) with Olivia Newton John, never knowing until today that it is from Coleridge’s Kubla Khan.  Well, maybe I did know that in some hazy literature era of days gone by…At any rate, I’m glad I (re)discovered it today.

http://allpoetry.com/poem/8439799-Kubla_Khan_Or__A_Vision_In_A_Dream._A_Fragment-by-Samuel_Taylor_Coleridge