21. Mastodon: Crack The Skye

Mastodon's cover art specialist Paul Romano came up with one of the best covers in recent times. The art consists of many images tied together into one, each of which has something to do with the album's concept. It deals with astral travel and out of body experiences, among other things. So, because he had the seemingly insurmountable task of making sense of all of that and put it into a single picture, Paul's artwork is just fantastic.