Things I would like the world to know before I die #1:
You don’t have to say “an historic”. A lot of people think this is harder than it actually is. The difference between a and an is purely phonetic. If the word following the indefinite article starts with a vowel sound it gets an “an”. This helps speakers avoid what is called a “glottal stop” allowing for the natural elision between words in English. Because “historic” is a word people often encounter in formal settings like fancy books and speeches, I have a sense that people think (as is the case with who/whom) that “an” helps make it fancy. It does not. In certain regions or dialects of English the “h” in “historic” is silent, and in those dialects using “an” makes sense. In all others it’s not necessary.