Pandemonium

Pandemonium is defined by the OED as:

A centre of vice or wickedness; a haunt of evil. Now: esp. a place or state of utter confusion and uproar; a noisy disorderly place.

Utter confusion, uproar; wild and noisy disorder; a tumult; chaos. (Now the usual sense).

It was first used in Milton's Paradise Lost as the capital of Hell. It was made from the Greek root pan meaning "all", and the Latin root daemonium meaning "demon", which itself comes from the Greek daimonion. So essentially when someone describes a place as being in pandemonium they are saying that it is full of demons.

-Oxford English Dictionary