Here's why it's there:
* Pronunciation: The acute accent indicates that the "e" is pronounced as a closed "e" sound, similar to the "e" in "bed." Without the accent, the "e" would be silent.
* Grammar: In French, the acute accent is used to distinguish between words that are spelled similarly but have different pronunciations and meanings. In this case, "bibliothèque" is pronounced differently from "bibliotheque" (without the accent), which would be a different word.
Therefore, the accent is essential for the correct pronunciation and spelling of the word "bibliothèque."