This is an heavenly, historical hotel. Really?
Things have changed. Language is ever changing, including how to use “a” and “an” before a word beginning with “h.” “An historical book” is no longer idiomatic in American English. Nor it is heavenly.
Before a pronounced “h,” the indefinite article should be “a.” A hotel; a historical. A heavenly.
Think of if this way: precede a word beginning with a “breathy” h with an “a.” Not an “an.”